Finishing Immutable changes including GLCapabiltiesImmutable.

69 files changed, 848 insertions, 469 deletions

diff --git a/src/jogl/classes/com/jogamp/opengl/impl/GLContextImpl.java b/src/jogl/classes/com/jogamp/opengl/impl/GLContextImpl.java
index 6c15a2d92..4892303e3 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/GLContextImpl.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/GLContextImpl.java
@@ -54,7 +54,7 @@ import javax.media.nativewindow.AbstractGraphicsConfiguration;
 import javax.media.nativewindow.AbstractGraphicsDevice;
 import javax.media.nativewindow.NativeSurface;
 import javax.media.opengl.GL;
-import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesImmutable;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawable;
 import javax.media.opengl.GLException;
@@ -499,7 +499,7 @@ public abstract class GLContextImpl extends GLContext {
   {
     AbstractGraphicsConfiguration config = drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
     AbstractGraphicsDevice device = config.getScreen().getDevice();
-    GLCapabilities glCaps = (GLCapabilities) config.getChosenCapabilities();
+    GLCapabilitiesImmutable glCaps = (GLCapabilitiesImmutable) config.getChosenCapabilities();
     GLProfile glp = glCaps.getGLProfile();
 
     if (DEBUG) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableFactoryImpl.java b/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableFactoryImpl.java
index 43f705e34..ef5f67081 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableFactoryImpl.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableFactoryImpl.java
@@ -71,7 +71,7 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
       throw new IllegalArgumentException("Null target");
     }
     AbstractGraphicsConfiguration config = target.getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities caps = (GLCapabilities) config.getChosenCapabilities();
+    GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable) config.getChosenCapabilities();
     AbstractGraphicsDevice adevice = config.getScreen().getDevice();
     GLDrawable result = null;
     adevice.lock();
@@ -131,7 +131,7 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
     return createGLPbufferDrawableImpl(target);
   }
   
-  public GLDrawable createGLPbufferDrawable(GLCapabilities capabilities,
+  public GLDrawable createGLPbufferDrawable(GLCapabilitiesImmutable capsRequested,
                                             GLCapabilitiesChooser chooser,
                                             int width,
                                             int height) {
@@ -139,18 +139,28 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
         throw new GLException("Width and height of pbuffer must be positive (were (" +
                         width + ", " + height + "))");
     }
-    capabilities.setDoubleBuffered(false); // FIXME DBLBUFOFFSCRN
-    capabilities.setOnscreen(false);
-    capabilities.setPBuffer(true);
+
+    GLCapabilitiesImmutable capsChosen;
+
+    if( capsRequested.getDoubleBuffered() || capsRequested.isOnscreen() || !capsRequested.isPBuffer()) {
+        // fix caps ..
+        GLCapabilities caps2 = (GLCapabilities) capsRequested.cloneMutable();
+        caps2.setDoubleBuffered(false); // FIXME DBLBUFOFFSCRN
+        caps2.setOnscreen(false);
+        caps2.setPBuffer(true);
+        capsChosen = caps2;
+    } else {
+        capsChosen = capsRequested;
+    }
     NativeWindowFactory.getDefaultToolkitLock().lock();
     try {
-        return createGLPbufferDrawable( createOffscreenSurfaceImpl(capabilities, chooser, height, height) );
+        return createGLPbufferDrawable( createOffscreenSurfaceImpl(capsChosen, capsRequested, chooser, height, height) );
     } finally {
         NativeWindowFactory.getDefaultToolkitLock().unlock();
     }
   }
 
-  public GLPbuffer createGLPbuffer(GLCapabilities capabilities,
+  public GLPbuffer createGLPbuffer(GLCapabilitiesImmutable capabilities,
                                    GLCapabilitiesChooser chooser,
                                    int width,
                                    int height,
@@ -167,7 +177,7 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
 
   protected abstract GLDrawableImpl createOffscreenDrawableImpl(NativeSurface target) ;
 
-  public GLDrawable createOffscreenDrawable(GLCapabilities capabilities,
+  public GLDrawable createOffscreenDrawable(GLCapabilitiesImmutable capsRequested,
                                             GLCapabilitiesChooser chooser,
                                             int width,
                                             int height) {
@@ -175,12 +185,21 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
         throw new GLException("Width and height of pbuffer must be positive (were (" +
                         width + ", " + height + "))");
     }
-    capabilities.setDoubleBuffered(false); // FIXME DBLBUFOFFSCRN
-    capabilities.setOnscreen(false);
-    capabilities.setPBuffer(false);
+    GLCapabilitiesImmutable capsChosen;
+
+    if( capsRequested.getDoubleBuffered() || capsRequested.isOnscreen() || capsRequested.isPBuffer()) {
+        // fix caps ..
+        GLCapabilities caps2 = (GLCapabilities) capsRequested.cloneMutable();
+        caps2.setDoubleBuffered(false); // FIXME DBLBUFOFFSCRN
+        caps2.setOnscreen(false);
+        caps2.setPBuffer(false);
+        capsChosen = caps2;
+    } else {
+        capsChosen = capsRequested;
+    }
     NativeWindowFactory.getDefaultToolkitLock().lock();
     try {
-        return createOffscreenDrawableImpl( createOffscreenSurfaceImpl(capabilities, chooser, width, height) );
+        return createOffscreenDrawableImpl( createOffscreenSurfaceImpl(capsChosen, capsRequested, chooser, width, height) );
     } finally {
         NativeWindowFactory.getDefaultToolkitLock().unlock();
     }
@@ -190,8 +209,9 @@ public abstract class GLDrawableFactoryImpl extends GLDrawableFactory {
    * creates an offscreen NativeSurface, which must implement SurfaceChangeable as well,
    * so the windowing system related implementation is able to set the surface handle.
    */
-  protected abstract NativeSurface createOffscreenSurfaceImpl(GLCapabilities capabilities, GLCapabilitiesChooser chooser,
-                                                        int width, int height);
+  protected abstract NativeSurface createOffscreenSurfaceImpl(GLCapabilitiesImmutable capabilities, GLCapabilitiesImmutable capsRequested,
+                                                              GLCapabilitiesChooser chooser,
+                                                              int width, int height);
 
   //---------------------------------------------------------------------------
   //
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableImpl.java b/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableImpl.java
index e68ee3644..d7d2836aa 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableImpl.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/GLDrawableImpl.java
@@ -52,7 +52,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
       this.factory = factory;
       this.surface = comp;
       this.realized = realized;
-      this.requestedCapabilities = (GLCapabilities)surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getRequestedCapabilities(); // a copy ..
+      this.requestedCapabilities = (GLCapabilitiesImmutable) surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getRequestedCapabilities();
   }
 
   /** 
@@ -79,7 +79,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
   }
 
   public final void swapBuffers() throws GLException {
-    GLCapabilities caps = (GLCapabilities)surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
+    GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
     if ( caps.getDoubleBuffered() ) {
         if(!surface.surfaceSwap()) {
             int lockRes = lockSurface(); // it's recursive, so it's ok within [makeCurrent .. release]
@@ -114,11 +114,11 @@ public abstract class GLDrawableImpl implements GLDrawable {
     return requestedCapabilities.getGLProfile();
   }
 
-  public GLCapabilities getChosenGLCapabilities() {
-    return  (GLCapabilities)surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities(); // a copy
+  public GLCapabilitiesImmutable getChosenGLCapabilities() {
+    return  (GLCapabilitiesImmutable) surface.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
   }
 
-  public GLCapabilities getRequestedGLCapabilities() {
+  public GLCapabilitiesImmutable getRequestedGLCapabilities() {
     return requestedCapabilities;
   }
 
@@ -204,7 +204,7 @@ public abstract class GLDrawableImpl implements GLDrawable {
 
   protected GLDrawableFactory factory;
   protected NativeSurface surface;
-  protected GLCapabilities requestedCapabilities;
+  protected GLCapabilitiesImmutable requestedCapabilities;
 
   // Indicates whether the surface (if an onscreen context) has been
   // realized. Plausibly, before the surface is realized the JAWT
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/GLPbufferImpl.java b/src/jogl/classes/com/jogamp/opengl/impl/GLPbufferImpl.java
index 7a30f9a6f..d282d2f84 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/GLPbufferImpl.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/GLPbufferImpl.java
@@ -64,7 +64,7 @@ public class GLPbufferImpl implements GLPbuffer {
 
   public GLPbufferImpl(GLDrawableImpl pbufferDrawable,
                        GLContext parentContext) {
-    GLCapabilities caps = (GLCapabilities) 
+    GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)
          pbufferDrawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
     if(caps.isOnscreen()) {
         if(caps.isPBuffer()) {
@@ -195,14 +195,14 @@ public class GLPbufferImpl implements GLPbuffer {
     context.releasePbufferFromTexture();
   }
 
-  public GLCapabilities getChosenGLCapabilities() {
+  public GLCapabilitiesImmutable getChosenGLCapabilities() {
     if (pbufferDrawable == null)
       return null;
 
     return pbufferDrawable.getChosenGLCapabilities();
   }
 
-  public GLCapabilities getRequestedGLCapabilities() {
+  public GLCapabilitiesImmutable getRequestedGLCapabilities() {
     if (pbufferDrawable == null)
       return null;
 
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawable.java
index 81dcc12d5..88685faf7 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawable.java
@@ -69,8 +69,8 @@ public abstract class EGLDrawable extends GLDrawableImpl {
         return eglConfig;
     }
 
-    public GLCapabilities getChosenGLCapabilities() {
-        return (null==eglConfig)?super.getChosenGLCapabilities():(GLCapabilities)eglConfig.getChosenCapabilities();
+    public GLCapabilitiesImmutable getChosenGLCapabilities() {
+        return (null==eglConfig)?super.getChosenGLCapabilities():(GLCapabilitiesImmutable)eglConfig.getChosenCapabilities();
     }
 
     public abstract GLContext createContext(GLContext shareWith);
@@ -168,8 +168,11 @@ public abstract class EGLDrawable extends GLDrawableImpl {
                 }
                 EGLGraphicsDevice e = new EGLGraphicsDevice(eglDisplay, AbstractGraphicsDevice.DEFAULT_UNIT);
                 DefaultGraphicsScreen s = new DefaultGraphicsScreen(e, aConfig.getScreen().getIndex());
-                GLCapabilities caps = (GLCapabilities) aConfig.getChosenCapabilities(); // yes, use the already choosen Capabilities (x11,win32,..)
-                eglConfig = (EGLGraphicsConfiguration) GraphicsConfigurationFactory.getFactory(e).chooseGraphicsConfiguration(caps, null, s);
+                // yes, use the already choosen/requested Capabilities (x11,win32,..)
+                GLCapabilitiesImmutable capsChosen = (GLCapabilitiesImmutable) aConfig.getChosenCapabilities();
+                GLCapabilitiesImmutable capsRequested = (GLCapabilitiesImmutable) aConfig.getRequestedCapabilities();
+                eglConfig = (EGLGraphicsConfiguration) GraphicsConfigurationFactory.getFactory(e).chooseGraphicsConfiguration(
+                        capsChosen, capsRequested, null, s);
                 if (null == eglConfig) {
                     throw new GLException("Couldn't create EGLGraphicsConfiguration from "+s);
                 } else if(DEBUG) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawableFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawableFactory.java
index 3c8c4c98f..737aa5519 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawableFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLDrawableFactory.java
@@ -163,8 +163,8 @@ public class EGLDrawableFactory extends GLDrawableFactoryImpl {
         return new EGLPbufferDrawable(this, target);
     }
 
-    protected NativeSurface createOffscreenSurfaceImpl(GLCapabilities capabilities, GLCapabilitiesChooser chooser, int width, int height) {
-        ProxySurface ns = new ProxySurface(EGLGraphicsConfigurationFactory.createOffscreenGraphicsConfiguration(capabilities, chooser));
+    protected NativeSurface createOffscreenSurfaceImpl(GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser, int width, int height) {
+        ProxySurface ns = new ProxySurface(EGLGraphicsConfigurationFactory.createOffscreenGraphicsConfiguration(capsChosen, capsRequested, chooser));
         ns.setSize(width, height);
         return ns;
     }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfiguration.java b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfiguration.java
index 2e4b06d94..dc74d3651 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfiguration.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfiguration.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -36,7 +37,6 @@
 package com.jogamp.opengl.impl.egl;
 
 import com.jogamp.common.nio.PointerBuffer;
-import java.util.*;
 import javax.media.nativewindow.*;
 import javax.media.nativewindow.egl.*;
 import javax.media.opengl.*;
@@ -54,7 +54,7 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
     }
 
     public EGLGraphicsConfiguration(AbstractGraphicsScreen absScreen, 
-                                    GLCapabilities capsChosen, GLCapabilities capsRequested, GLCapabilitiesChooser chooser,
+                                    GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser,
                                     long cfg, int cfgID) {
         super(absScreen, capsChosen, capsRequested);
         this.chooser = chooser;
@@ -62,7 +62,7 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
         configID = cfgID;
     }
 
-    public static EGLGraphicsConfiguration create(GLCapabilities capsRequested, AbstractGraphicsScreen absScreen, int cfgID) {
+    public static EGLGraphicsConfiguration create(GLCapabilitiesImmutable capsRequested, AbstractGraphicsScreen absScreen, int cfgID) {
         AbstractGraphicsDevice absDevice = absScreen.getDevice();
         if(null==absDevice || !(absDevice instanceof EGLGraphicsDevice)) {
             throw new GLException("GraphicsDevice must be a valid EGLGraphicsDevice");
@@ -73,7 +73,7 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
         }
         GLProfile glp = capsRequested.getGLProfile();
         long cfg = EGLConfigId2EGLConfig(glp, dpy, cfgID);
-        GLCapabilities caps = EGLConfig2Capabilities(glp, dpy, cfg, false, capsRequested.isOnscreen(), capsRequested.isPBuffer());
+        GLCapabilitiesImmutable caps = EGLConfig2Capabilities(glp, dpy, cfg, false, capsRequested.isOnscreen(), capsRequested.isPBuffer());
         return new EGLGraphicsConfiguration(absScreen, caps, capsRequested, new DefaultGLCapabilitiesChooser(), cfg, cfgID);
     }
 
@@ -83,9 +83,8 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
 
     protected void updateGraphicsConfiguration() {
         EGLGraphicsConfiguration newConfig = (EGLGraphicsConfiguration)
-            GraphicsConfigurationFactory.getFactory(getScreen().getDevice()).chooseGraphicsConfiguration(getRequestedCapabilities().cloneCapabilites(),
-                                                                                                         chooser,
-                                                                                                         getScreen());
+            GraphicsConfigurationFactory.getFactory(getScreen().getDevice()).chooseGraphicsConfiguration(
+                getChosenCapabilities(), getRequestedCapabilities(), chooser, getScreen());
         if(null!=newConfig) {
             // FIXME: setScreen( ... );
             setChosenCapabilities(newConfig.getChosenCapabilities());
@@ -132,8 +131,8 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
         return res;
     }
 
-    public static GLCapabilities EGLConfig2Capabilities(GLProfile glp, long display, long config, 
-                                                        boolean relaxed, boolean onscreen, boolean usePBuffer) {
+    public static GLCapabilitiesImmutable EGLConfig2Capabilities(GLProfile glp, long display, long config,
+                                                                 boolean relaxed, boolean onscreen, boolean usePBuffer) {
         GLCapabilities caps = new GLCapabilities(glp);
         int[] val = new int[1];
 
@@ -200,7 +199,7 @@ public class EGLGraphicsConfiguration extends DefaultGraphicsConfiguration imple
         return caps;
     }
 
-    public static int[] GLCapabilities2AttribList(GLCapabilities caps) {
+    public static int[] GLCapabilities2AttribList(GLCapabilitiesImmutable caps) {
         int[] attrs = new int[32];
         int idx=0;
 
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfigurationFactory.java
index c678707fc..8f0f036aa 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLGraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -32,12 +33,25 @@
 
 package com.jogamp.opengl.impl.egl;
 
-import com.jogamp.common.nio.PointerBuffer;
 import java.io.PrintStream;
-import javax.media.nativewindow.*;
-import javax.media.nativewindow.egl.*;
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.AbstractGraphicsDevice;
+import javax.media.nativewindow.AbstractGraphicsScreen;
+import javax.media.nativewindow.CapabilitiesChooser;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.nativewindow.DefaultGraphicsScreen;
+import javax.media.nativewindow.GraphicsConfigurationFactory;
+import javax.media.nativewindow.NativeWindowException;
+import javax.media.nativewindow.egl.EGLGraphicsDevice;
+
+import javax.media.opengl.DefaultGLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLException;
+import javax.media.opengl.GLProfile;
 
-import javax.media.opengl.*;
+import com.jogamp.common.nio.PointerBuffer;
 
 
 /** Subclass of GraphicsConfigurationFactory used when non-AWT tookits
@@ -54,14 +68,18 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl (
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+            CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
         if (absScreen == null) {
             throw new IllegalArgumentException("This NativeWindowFactory accepts only AbstractGraphicsDevice objects");
         }
 
-        if (capabilities != null &&
-            !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects");
+        if (! (capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if (! (capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null &&
@@ -69,18 +87,20 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
             throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilitiesChooser objects");
         }
 
-        return chooseGraphicsConfigurationStatic((GLCapabilities) capabilities,
+        return chooseGraphicsConfigurationStatic((GLCapabilitiesImmutable) capsChosen,
+                                                 (GLCapabilitiesImmutable) capsRequested,
                                                  (GLCapabilitiesChooser) chooser,
                                                  absScreen);
     }
 
-    private static EGLGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilities capabilities,
-                                                                             GLCapabilitiesChooser chooser,
-                                                                             AbstractGraphicsScreen absScreen) {
-        if (capabilities == null) {
-            capabilities = new GLCapabilities(null);
-        }
-        GLProfile glp = capabilities.getGLProfile();
+    private static EGLGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilitiesImmutable capsChosen,
+                                                                              GLCapabilitiesImmutable capsReq,
+                                                                              GLCapabilitiesChooser chooser,
+                                                                              AbstractGraphicsScreen absScreen) {
+        if (capsChosen == null) {
+            capsChosen = new GLCapabilities(null);
+        }
+        GLProfile glp = capsChosen.getGLProfile();
 
         if(null==absScreen) {
             throw new GLException("Null AbstractGraphicsScreen");
@@ -96,18 +116,19 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
             throw new GLException("Invalid EGL display: "+absDevice);
         }
 
-        GLCapabilities caps2 = (GLCapabilities) capabilities.clone();
-        if(!caps2.isOnscreen()) {
+        if(!capsChosen.isOnscreen() && capsChosen.getDoubleBuffered()) {
             // OFFSCREEN !DOUBLE_BUFFER // FIXME DBLBUFOFFSCRN
+            GLCapabilities caps2 = (GLCapabilities) capsChosen.cloneMutable();
             caps2.setDoubleBuffered(false);
+            capsChosen = caps2;
         }
 
-        EGLGraphicsConfiguration res = eglChooseConfig(eglDisplay, caps2, capabilities, chooser, absScreen);
+        EGLGraphicsConfiguration res = eglChooseConfig(eglDisplay, capsChosen, capsReq, chooser, absScreen);
         if(null!=res) {
             return res;
         }
         if(DEBUG) {
-            System.err.println("eglChooseConfig failed with given capabilities "+caps2);
+            System.err.println("eglChooseConfig failed with given capabilities "+capsChosen);
         }
 
         if (chooser == null) {
@@ -123,15 +144,15 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         if (numConfigs[0] == 0) {
             throw new GLException("Graphics configuration fetch (eglGetConfigs) - no EGLConfig found");
         }
-        GLCapabilities[] caps = eglConfigs2GLCaps(glp, eglDisplay, configs, numConfigs[0],
-                                                    caps2.isOnscreen(), caps2.isPBuffer());
+        GLCapabilitiesImmutable[] caps = eglConfigs2GLCaps(glp, eglDisplay, configs, numConfigs[0],
+                                                           capsChosen.isOnscreen(), capsChosen.isPBuffer());
         if(DEBUG) {
             System.err.println("EGL Get Configs: "+numConfigs[0]+", Caps "+caps.length);
             printCaps("eglGetConfigs", caps, System.err);
         }
         int chosen = -1;
         try {
-            chosen = chooser.chooseCapabilities(caps2, caps, -1);
+            chosen = chooser.chooseCapabilities(capsChosen, caps, -1);
         } catch (NativeWindowException e) { throw new GLException(e); }
         if(chosen<0) {
             throw new GLException("Graphics configuration chooser failed");
@@ -139,7 +160,7 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         if(DEBUG) {
             System.err.println("Chosen "+caps[chosen]);
         }
-        res = eglChooseConfig(eglDisplay, caps[chosen], capabilities, chooser, absScreen);
+        res = eglChooseConfig(eglDisplay, caps[chosen], capsReq, chooser, absScreen);
         if(null!=res) {
             return res;
         }
@@ -160,7 +181,7 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         if(DEBUG) {
             System.err.println("trying fixed caps (1): "+fixedCaps);
         }
-        res = eglChooseConfig(eglDisplay, fixedCaps, capabilities, chooser, absScreen);
+        res = eglChooseConfig(eglDisplay, fixedCaps, capsReq, chooser, absScreen);
         if(null!=res) {
             return res;
         }
@@ -175,7 +196,7 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         if(DEBUG) {
             System.err.println("trying fixed caps (2): "+fixedCaps);
         }
-        res = eglChooseConfig(eglDisplay, fixedCaps, capabilities, chooser, absScreen);
+        res = eglChooseConfig(eglDisplay, fixedCaps, capsReq, chooser, absScreen);
         if(null!=res) {
             return res;
         }
@@ -192,7 +213,7 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         if(DEBUG) {
             System.err.println("trying fixed caps (3): "+fixedCaps);
         }
-        res = eglChooseConfig(eglDisplay, fixedCaps, capabilities, chooser, absScreen);
+        res = eglChooseConfig(eglDisplay, fixedCaps, capsReq, chooser, absScreen);
         if(null!=res) {
             return res;
         }
@@ -200,7 +221,8 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
     }
 
     protected static EGLGraphicsConfiguration eglChooseConfig(long eglDisplay, 
-                                                              GLCapabilities capsChosen0, GLCapabilities capsRequested, GLCapabilitiesChooser chooser,
+                                                              GLCapabilitiesImmutable capsChosen0, GLCapabilitiesImmutable capsRequested,
+                                                              GLCapabilitiesChooser chooser,
                                                               AbstractGraphicsScreen absScreen) {
         GLProfile glp = capsChosen0.getGLProfile();
         int[] attrs = EGLGraphicsConfiguration.GLCapabilities2AttribList(capsChosen0);
@@ -214,8 +236,8 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         }
         if (numConfigs[0] > 0) {
             if(DEBUG) {
-                GLCapabilities[] caps = eglConfigs2GLCaps(glp, eglDisplay, configs, numConfigs[0],
-                                                    capsChosen0.isOnscreen(), capsChosen0.isPBuffer());
+                GLCapabilitiesImmutable[] caps = eglConfigs2GLCaps(glp, eglDisplay, configs, numConfigs[0],
+                                                                   capsChosen0.isOnscreen(), capsChosen0.isPBuffer());
                 System.err.println("EGL Choose Configs: "+numConfigs[0]+", Caps "+caps.length);
                 printCaps("eglChooseConfig", caps, System.err);
             }
@@ -228,8 +250,9 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
                 }
                 return null;
             }
-            GLCapabilities capsChosen1 = EGLGraphicsConfiguration.EGLConfig2Capabilities(glp, eglDisplay, configs.get(0),
-                                                                    true, capsChosen0.isOnscreen(), capsChosen0.isPBuffer());
+            GLCapabilitiesImmutable capsChosen1 = EGLGraphicsConfiguration.EGLConfig2Capabilities(
+                                                            glp, eglDisplay, configs.get(0),
+                                                            true, capsChosen0.isOnscreen(), capsChosen0.isPBuffer());
             if(null!=capsChosen1) {
                 if(DEBUG) {
                     System.err.println("eglChooseConfig found: eglDisplay 0x"+Long.toHexString(eglDisplay)+
@@ -252,27 +275,34 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         return null;
     }
 
-    protected static GLCapabilities[] eglConfigs2GLCaps(GLProfile glp, long eglDisplay, PointerBuffer configs, int num,
-                                                        boolean onscreen, boolean usePBuffer) {
-        GLCapabilities[] caps = new GLCapabilities[num];
+    protected static GLCapabilitiesImmutable[] eglConfigs2GLCaps(GLProfile glp, long eglDisplay, PointerBuffer configs, int num,
+                                                                 boolean onscreen, boolean usePBuffer) {
+        GLCapabilitiesImmutable[] caps = new GLCapabilitiesImmutable[num];
         for(int i=0; i<num; i++) {
             caps[i] = EGLGraphicsConfiguration.EGLConfig2Capabilities(glp, eglDisplay, configs.get(i),
-                                            true, onscreen, usePBuffer);
+                                                                      true, onscreen, usePBuffer);
         }
         return caps;
     }
 
-    protected static void printCaps(String prefix, GLCapabilities[] caps, PrintStream out) {
+    protected static void printCaps(String prefix, GLCapabilitiesImmutable[] caps, PrintStream out) {
         for(int i=0; i<caps.length; i++) {
             out.println(prefix+"["+i+"] "+caps[i]);
         }
     }
 
-    protected static EGLGraphicsConfiguration createOffscreenGraphicsConfiguration(GLCapabilities caps, GLCapabilitiesChooser chooser) {
-        if(caps.isOnscreen()) {
-            throw new GLException("Error: Onscreen set: "+caps);
+    protected static EGLGraphicsConfiguration createOffscreenGraphicsConfiguration(GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsReq, GLCapabilitiesChooser chooser) {
+        if(capsChosen.isOnscreen()) {
+            throw new GLException("Error: Onscreen set: "+capsChosen);
         }
-        caps.setDoubleBuffered(false); // FIXME DBLBUFOFFSCRN
+
+        if(capsChosen.getDoubleBuffered()) {
+            // OFFSCREEN !DOUBLE_BUFFER // FIXME DBLBUFOFFSCRN
+            GLCapabilities caps2 = (GLCapabilities) capsChosen.cloneMutable();
+            caps2.setDoubleBuffered(false);
+            capsChosen = caps2;
+        }
+
         long eglDisplay = EGL.eglGetDisplay(EGL.EGL_DEFAULT_DISPLAY);
         if (eglDisplay == EGL.EGL_NO_DISPLAY) {
             throw new GLException("Failed to created EGL default display: error 0x"+Integer.toHexString(EGL.eglGetError()));
@@ -284,7 +314,7 @@ public class EGLGraphicsConfigurationFactory extends GraphicsConfigurationFactor
         }
         EGLGraphicsDevice e = new EGLGraphicsDevice(eglDisplay, AbstractGraphicsDevice.DEFAULT_UNIT);
         DefaultGraphicsScreen s = new DefaultGraphicsScreen(e, 0);
-        EGLGraphicsConfiguration eglConfig = chooseGraphicsConfigurationStatic(caps, chooser, s);
+        EGLGraphicsConfiguration eglConfig = chooseGraphicsConfigurationStatic(capsChosen, capsReq, chooser, s);
         if (null == eglConfig) {
             EGL.eglTerminate(eglDisplay);
             throw new GLException("Couldn't create EGLGraphicsConfiguration from "+s);
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLPbufferDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLPbufferDrawable.java
index e633d0b47..3189324d1 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLPbufferDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/egl/EGLPbufferDrawable.java
@@ -40,8 +40,11 @@
 
 package com.jogamp.opengl.impl.egl;
 
-import javax.media.opengl.*;
-import javax.media.nativewindow.*;
+import javax.media.nativewindow.NativeSurface;
+import javax.media.nativewindow.SurfaceChangeable;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLContext;
+import javax.media.opengl.GLException;
 
 public class EGLPbufferDrawable extends EGLDrawable {
     private int texFormat;
@@ -52,7 +55,8 @@ public class EGLPbufferDrawable extends EGLDrawable {
         ownEGLDisplay = true;
 
         // get choosen ones ..
-        GLCapabilities caps = (GLCapabilities) getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
+        GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)
+                   getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
 
         if(useTexture) {
             this.texFormat = caps.getAlphaBits() > 0 ? EGL.EGL_TEXTURE_RGBA : EGL.EGL_TEXTURE_RGB ;
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLContext.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLContext.java
index e9b543721..3cd2aa650 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLContext.java
@@ -116,13 +116,13 @@ public abstract class MacOSXCGLContext extends GLContextImpl
       }
     }
     MacOSXCGLGraphicsConfiguration config = (MacOSXCGLGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities capabilitiesRequested = (GLCapabilities)config.getRequestedCapabilities();
+    GLCapabilitiesImmutable capabilitiesRequested = (GLCapabilitiesImmutable) config.getRequestedCapabilities();
     GLProfile glProfile = capabilitiesRequested.getGLProfile();
     if(glProfile.isGL3()) {
         throw new GLException("GL3 profile currently not supported on MacOSX, due to the lack of a OpenGL 3.1 implementation");
     }
     // HACK .. bring in OnScreen/PBuffer selection to the DrawableFactory !!
-    GLCapabilities capabilities = (GLCapabilities) capabilitiesRequested.clone();
+    GLCapabilities capabilities = (GLCapabilities) capabilitiesRequested.cloneMutable();
     capabilities.setPBuffer(pbuffer);
     capabilities.setPbufferFloatingPointBuffers(floatingPoint);
 
@@ -154,7 +154,7 @@ public abstract class MacOSXCGLContext extends GLContextImpl
           CGL.setContextOpacity(contextHandle, 0);
       }
 
-      GLCapabilities caps = MacOSXCGLGraphicsConfiguration.NSPixelFormat2GLCapabilities(glProfile, pixelFormat);
+      GLCapabilitiesImmutable caps = MacOSXCGLGraphicsConfiguration.NSPixelFormat2GLCapabilities(glProfile, pixelFormat);
       config.setChosenCapabilities(caps);
     } finally {
       CGL.deletePixelFormat(pixelFormat);
@@ -260,7 +260,7 @@ public abstract class MacOSXCGLContext extends GLContextImpl
 	
   protected void swapBuffers() {
     DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities caps = (GLCapabilities)config.getChosenCapabilities();
+    GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)config.getChosenCapabilities();
     if(caps.isOnscreen()) {
         if(isNSContext) {
             if (!CGL.flushBuffer(contextHandle)) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLDrawableFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLDrawableFactory.java
index a8a82b46a..71b99c2d5 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLDrawableFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLDrawableFactory.java
@@ -151,9 +151,9 @@ public class MacOSXCGLDrawableFactory extends GLDrawableFactoryImpl {
     return new MacOSXPbufferCGLDrawable(this, target);
   }
 
-  protected NativeSurface createOffscreenSurfaceImpl(GLCapabilities capabilities, GLCapabilitiesChooser chooser, int width, int height) {
+  protected NativeSurface createOffscreenSurfaceImpl(GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser, int width, int height) {
     AbstractGraphicsScreen screen = DefaultGraphicsScreen.createDefault(NativeWindowFactory.TYPE_MACOSX);
-    ProxySurface ns = new ProxySurface(MacOSXCGLGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(capabilities, chooser, screen, true));
+    ProxySurface ns = new ProxySurface(MacOSXCGLGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(capsChosen, capsRequested, chooser, screen, true));
     ns.setSize(width, height);
     return ns;
   }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfiguration.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfiguration.java
index d2be9d0de..b912efd1f 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfiguration.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfiguration.java
@@ -42,7 +42,8 @@ import javax.media.opengl.*;
 public class MacOSXCGLGraphicsConfiguration extends DefaultGraphicsConfiguration implements Cloneable {
     long pixelformat;
 
-    public MacOSXCGLGraphicsConfiguration(AbstractGraphicsScreen screen, GLCapabilities capsChosen, GLCapabilities capsRequested,
+    public MacOSXCGLGraphicsConfiguration(AbstractGraphicsScreen screen, 
+                                          GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested,
                                           long pixelformat) {
         super(screen, capsChosen, capsRequested);
         this.pixelformat=pixelformat;
@@ -56,7 +57,7 @@ public class MacOSXCGLGraphicsConfiguration extends DefaultGraphicsConfiguration
         this.pixelformat=pixelformat;
     }
 
-    protected void setChosenCapabilities(GLCapabilities caps) {
+    protected void setChosenCapabilities(GLCapabilitiesImmutable caps) {
         super.setChosenCapabilities(caps);
     }
 
@@ -73,7 +74,7 @@ public class MacOSXCGLGraphicsConfiguration extends DefaultGraphicsConfiguration
         CGL.NSOpenGLPFASampleBuffers,
         CGL.NSOpenGLPFASamples };
 
-    protected static int[] GLCapabilities2AttribList(GLCapabilities caps) {
+    protected static int[] GLCapabilities2AttribList(GLCapabilitiesImmutable caps) {
         int[] ivalues = new int[cglInternalAttributeToken.length];
 
         for (int idx = 0; idx < cglInternalAttributeToken.length; idx++) {
@@ -130,20 +131,20 @@ public class MacOSXCGLGraphicsConfiguration extends DefaultGraphicsConfiguration
         return ivalues;
     }
 
-    protected static long GLCapabilities2NSPixelFormat(GLCapabilities caps) {
+    protected static long GLCapabilities2NSPixelFormat(GLCapabilitiesImmutable caps) {
         int[] ivalues = GLCapabilities2AttribList(caps);
         return CGL.createPixelFormat(cglInternalAttributeToken, 0, cglInternalAttributeToken.length, ivalues, 0);
     }
 
-    protected static GLCapabilities NSPixelFormat2GLCapabilities(GLProfile glp, long pixelFormat) {
+    protected static GLCapabilitiesImmutable NSPixelFormat2GLCapabilities(GLProfile glp, long pixelFormat) {
         return PixelFormat2GLCapabilities(glp, pixelFormat, true);
     }
 
-    protected static GLCapabilities CGLPixelFormat2GLCapabilities(GLProfile glp, long pixelFormat) {
+    protected static GLCapabilitiesImmutable CGLPixelFormat2GLCapabilities(GLProfile glp, long pixelFormat) {
         return PixelFormat2GLCapabilities(glp, pixelFormat, false);
     }
 
-    private static GLCapabilities PixelFormat2GLCapabilities(GLProfile glp, long pixelFormat, boolean nsUsage) {
+    private static GLCapabilitiesImmutable PixelFormat2GLCapabilities(GLProfile glp, long pixelFormat, boolean nsUsage) {
         int[] ivalues = new int[cglInternalAttributeToken.length];
 
         // On this platform the pixel format is associated with the
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfigurationFactory.java
index 69bb245e1..f53fff168 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXCGLGraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -32,12 +33,14 @@
 
 package com.jogamp.opengl.impl.macosx.cgl;
 
-import javax.media.nativewindow.*;
-import javax.media.nativewindow.macosx.*;
-import com.jogamp.nativewindow.impl.*;
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.AbstractGraphicsScreen;
+import javax.media.nativewindow.CapabilitiesChooser;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.nativewindow.GraphicsConfigurationFactory;
+import javax.media.opengl.GLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
-import javax.media.opengl.*;
-import com.jogamp.opengl.impl.*;
 
 /** Subclass of GraphicsConfigurationFactory used when non-AWT tookits
     are used on OSX platforms. Toolkits will likely need to delegate
@@ -52,20 +55,25 @@ public class MacOSXCGLGraphicsConfigurationFactory extends GraphicsConfiguration
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
-        return chooseGraphicsConfigurationStatic(capabilities, chooser, absScreen, false);
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+            CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+        return chooseGraphicsConfigurationStatic(capsChosen, capsRequested, chooser, absScreen, false);
     }
 
-    protected static MacOSXCGLGraphicsConfiguration chooseGraphicsConfigurationStatic(Capabilities capabilities,
-                                                                                   CapabilitiesChooser chooser,
-                                                                                   AbstractGraphicsScreen absScreen, boolean usePBuffer) {
+    protected static MacOSXCGLGraphicsConfiguration chooseGraphicsConfigurationStatic(CapabilitiesImmutable capsChosen,
+                                                                                      CapabilitiesImmutable capsRequested,
+                                                                                      CapabilitiesChooser chooser,
+                                                                                      AbstractGraphicsScreen absScreen, boolean usePBuffer) {
         if (absScreen == null) {
             throw new IllegalArgumentException("AbstractGraphicsScreen is null");
         }
 
-        if (capabilities != null &&
-            !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects");
+        if (! (capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if (! (capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null &&
@@ -73,11 +81,6 @@ public class MacOSXCGLGraphicsConfigurationFactory extends GraphicsConfiguration
             throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilitiesChooser objects");
         }
 
-        if (capabilities == null) {
-            capabilities = new GLCapabilities(null);
-        }
-
-        return new MacOSXCGLGraphicsConfiguration(absScreen, (GLCapabilities)capabilities, (GLCapabilities)capabilities, 0);
+        return new MacOSXCGLGraphicsConfiguration(absScreen, (GLCapabilitiesImmutable)capsChosen, (GLCapabilitiesImmutable)capsRequested, 0);
     }
 }
-
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXExternalCGLContext.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXExternalCGLContext.java
index 5dcc103b2..80a396a29 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXExternalCGLContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXExternalCGLContext.java
@@ -92,7 +92,7 @@ public class MacOSXExternalCGLContext extends MacOSXCGLContext {
     if (0 == pixelFormat) {
       throw new GLException("Error: current pixelformat of current Context 0x"+Long.toHexString(contextHandle)+" is null");
     }
-    GLCapabilities caps = MacOSXCGLGraphicsConfiguration.CGLPixelFormat2GLCapabilities(glp, pixelFormat);
+    GLCapabilitiesImmutable caps = MacOSXCGLGraphicsConfiguration.CGLPixelFormat2GLCapabilities(glp, pixelFormat);
     if(DEBUG) {
         System.err.println("MacOSXExternalCGLContext Create "+caps);
     }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLContext.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLContext.java
index 5cf8c6eb9..93e5767b3 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLContext.java
@@ -87,7 +87,7 @@ public class MacOSXPbufferCGLContext extends MacOSXCGLContext {
     if (newCreated) {
       // Initialize render-to-texture support if requested
       DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-      GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+      GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
       GL gl = getGL();
       boolean rect = gl.isGL2GL3() && capabilities.getPbufferRenderToTextureRectangle();
       if (rect) {
@@ -136,7 +136,7 @@ public class MacOSXPbufferCGLContext extends MacOSXCGLContext {
 
   protected boolean createImpl() throws GLException {
     DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+    GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
     if (capabilities.getPbufferFloatingPointBuffers() &&
 	!isTigerOrLater) {
       throw new GLException("Floating-point pbuffers supported only on OS X 10.4 or later");
@@ -224,7 +224,7 @@ public class MacOSXPbufferCGLContext extends MacOSXCGLContext {
     public boolean isNSContext() { return true; }
     public long create() {
       DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-      GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+      GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
       if (capabilities.getPbufferFloatingPointBuffers() &&
           !isTigerOrLater) {
         throw new GLException("Floating-point pbuffers supported only on OS X 10.4 or later");
@@ -288,7 +288,7 @@ public class MacOSXPbufferCGLContext extends MacOSXCGLContext {
       int i = 0;
       attrs[i++] = CGL.kCGLPFAPBuffer;
       DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-      GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+      GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
       if (capabilities.getPbufferFloatingPointBuffers())
         attrs[i++] = CGL.kCGLPFAColorFloat;
       if (capabilities.getDoubleBuffered())
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLDrawable.java
index 14ed02918..37c6cfb70 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/MacOSXPbufferCGLDrawable.java
@@ -110,7 +110,7 @@ public class MacOSXPbufferCGLDrawable extends MacOSXCGLDrawable {
   private void createPbuffer() {
     NativeSurface ns = getNativeSurface();
     DefaultGraphicsConfiguration config = (DefaultGraphicsConfiguration) ns.getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+    GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
     GLProfile glProfile = capabilities.getGLProfile();
     int renderTarget;
     if (glProfile.isGL2GL3() && capabilities.getPbufferRenderToTextureRectangle()) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/awt/MacOSXAWTCGLGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/awt/MacOSXAWTCGLGraphicsConfigurationFactory.java
index af8841d3d..690e0466b 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/awt/MacOSXAWTCGLGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/macosx/cgl/awt/MacOSXAWTCGLGraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -34,17 +35,24 @@ package com.jogamp.opengl.impl.macosx.cgl.awt;
 
 import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsDevice;
-import java.awt.GraphicsEnvironment;
-import javax.media.nativewindow.*;
-import javax.media.nativewindow.macosx.*;
-import javax.media.nativewindow.awt.*;
-import javax.media.opengl.*;
-import javax.media.opengl.awt.*;
-
-import com.jogamp.opengl.impl.*;
-import com.jogamp.opengl.impl.macosx.cgl.*;
-import com.jogamp.nativewindow.impl.jawt.*;
-import com.jogamp.nativewindow.impl.jawt.macosx.*;
+
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.AbstractGraphicsDevice;
+import javax.media.nativewindow.AbstractGraphicsScreen;
+import javax.media.nativewindow.CapabilitiesChooser;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.nativewindow.DefaultGraphicsScreen;
+import javax.media.nativewindow.GraphicsConfigurationFactory;
+import javax.media.nativewindow.awt.AWTGraphicsConfiguration;
+import javax.media.nativewindow.awt.AWTGraphicsDevice;
+import javax.media.nativewindow.awt.AWTGraphicsScreen;
+import javax.media.nativewindow.macosx.MacOSXGraphicsDevice;
+
+import javax.media.opengl.GLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLException;
+
+import com.jogamp.opengl.impl.macosx.cgl.MacOSXCGLGraphicsConfiguration;
 
 public class MacOSXAWTCGLGraphicsConfigurationFactory extends GraphicsConfigurationFactory {
     protected static final boolean DEBUG = com.jogamp.opengl.impl.Debug.debug("GraphicsConfiguration");
@@ -54,7 +62,8 @@ public class MacOSXAWTCGLGraphicsConfigurationFactory extends GraphicsConfigurat
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+            CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
         GraphicsDevice device = null;
         if (absScreen != null &&
             !(absScreen instanceof AWTGraphicsScreen)) {
@@ -67,9 +76,12 @@ public class MacOSXAWTCGLGraphicsConfigurationFactory extends GraphicsConfigurat
         AWTGraphicsScreen awtScreen = (AWTGraphicsScreen) absScreen;
         device = ((AWTGraphicsDevice)awtScreen.getDevice()).getGraphicsDevice();
 
-        if (capabilities != null &&
-            !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects");
+        if ( !(capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if ( !(capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null &&
@@ -81,8 +93,6 @@ public class MacOSXAWTCGLGraphicsConfigurationFactory extends GraphicsConfigurat
             System.err.println("MacOSXAWTCGLGraphicsConfigurationFactory: got "+absScreen);
         }
 
-        long displayHandle = 0;
-
         MacOSXGraphicsDevice macDevice = new MacOSXGraphicsDevice(AbstractGraphicsDevice.DEFAULT_UNIT);
         DefaultGraphicsScreen macScreen = new DefaultGraphicsScreen(macDevice, awtScreen.getIndex());
         if(DEBUG) {
@@ -90,18 +100,18 @@ public class MacOSXAWTCGLGraphicsConfigurationFactory extends GraphicsConfigurat
         }
 
         GraphicsConfiguration gc = device.getDefaultConfiguration();
-        AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capabilities, gc);
+        capsChosen = (GLCapabilitiesImmutable) AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capsChosen, gc);
         if(DEBUG) {
-            System.err.println("AWT Colormodel compatible: "+capabilities);
+            System.err.println("AWT Colormodel compatible: "+capsChosen);
         }
 
         MacOSXCGLGraphicsConfiguration macConfig = (MacOSXCGLGraphicsConfiguration)
-            GraphicsConfigurationFactory.getFactory(macDevice).chooseGraphicsConfiguration(capabilities,
-                                                                                           chooser,
-                                                                                           macScreen);
+            GraphicsConfigurationFactory.getFactory(macDevice).chooseGraphicsConfiguration(capsChosen,
+                                                                                           capsRequested,
+                                                                                           chooser, macScreen);
 
         if (macConfig == null) {
-            throw new GLException("Unable to choose a GraphicsConfiguration: "+capabilities+",\n\t"+chooser+"\n\t"+macScreen);
+            throw new GLException("Unable to choose a GraphicsConfiguration: "+capsChosen+",\n\t"+chooser+"\n\t"+macScreen);
         }
 
         // FIXME: we have nothing to match .. so choose the default
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsDummyWGLDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsDummyWGLDrawable.java
index 3f7028d56..054c01fdb 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsDummyWGLDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsDummyWGLDrawable.java
@@ -40,7 +40,6 @@
 
 package com.jogamp.opengl.impl.windows.wgl;
 
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawableFactory;
 import javax.media.opengl.GLProfile;
@@ -48,12 +47,14 @@ import javax.media.opengl.GLProfile;
 import com.jogamp.nativewindow.impl.ProxySurface;
 import com.jogamp.nativewindow.impl.windows.GDI;
 import com.jogamp.nativewindow.impl.windows.PIXELFORMATDESCRIPTOR;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class WindowsDummyWGLDrawable extends WindowsWGLDrawable {
   private long hwnd, hdc;
 
-  public WindowsDummyWGLDrawable(GLDrawableFactory factory, GLProfile glp) {
-    super(factory, new ProxySurface(WindowsWGLGraphicsConfigurationFactory.createDefaultGraphicsConfiguration(glp, null, true, true)), true);
+  protected WindowsDummyWGLDrawable(GLDrawableFactory factory, GLCapabilitiesImmutable caps) {
+    super(factory, new ProxySurface(WindowsWGLGraphicsConfigurationFactory.createDefaultGraphicsConfiguration(caps, null)), true);
     // All entries to CreateDummyWindow must synchronize on one object
     // to avoid accidentally registering the dummy window class twice
     synchronized (WindowsDummyWGLDrawable.class) {
@@ -64,9 +65,7 @@ public class WindowsDummyWGLDrawable extends WindowsWGLDrawable {
     ns.setSurfaceHandle(hdc);
     WindowsWGLGraphicsConfiguration config = (WindowsWGLGraphicsConfiguration)ns.getGraphicsConfiguration().getNativeGraphicsConfiguration();
     // Choose a (hopefully hardware-accelerated) OpenGL pixel format for this device context
-    GLCapabilities caps = (GLCapabilities) config.getChosenCapabilities();
-    caps.setDepthBits(16);
-    PIXELFORMATDESCRIPTOR pfd = WindowsWGLGraphicsConfiguration.GLCapabilities2PFD(caps);
+    PIXELFORMATDESCRIPTOR pfd = WindowsWGLGraphicsConfiguration.GLCapabilities2PFD((GLCapabilitiesImmutable)config.getChosenCapabilities());
     int pixelFormat = GDI.ChoosePixelFormat(hdc, pfd);
     if ((pixelFormat == 0) ||
         (!GDI.SetPixelFormat(hdc, pixelFormat, pfd))) {
@@ -74,6 +73,15 @@ public class WindowsDummyWGLDrawable extends WindowsWGLDrawable {
     }
   }
 
+  public static WindowsDummyWGLDrawable create(GLDrawableFactory factory, GLProfile glp) {
+      GLCapabilities caps = new GLCapabilities(glp);
+      caps.setDepthBits(16);
+      caps.setDoubleBuffered(true);
+      caps.setOnscreen  (true);
+      caps.setPBuffer   (true);
+      return new WindowsDummyWGLDrawable(factory, caps);
+  }
+
   public void setSize(int width, int height) {
   }
 
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsOffscreenWGLDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsOffscreenWGLDrawable.java
index 8bb781a45..3452d3b55 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsOffscreenWGLDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsOffscreenWGLDrawable.java
@@ -42,7 +42,6 @@ package com.jogamp.opengl.impl.windows.wgl;
 
 import javax.media.nativewindow.NativeSurface;
 import javax.media.nativewindow.SurfaceChangeable;
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawableFactory;
 import javax.media.opengl.GLException;
@@ -50,6 +49,7 @@ import javax.media.opengl.GLException;
 import com.jogamp.nativewindow.impl.windows.BITMAPINFO;
 import com.jogamp.nativewindow.impl.windows.BITMAPINFOHEADER;
 import com.jogamp.nativewindow.impl.windows.GDI;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class WindowsOffscreenWGLDrawable extends WindowsWGLDrawable {
   private long origbitmap;
@@ -75,7 +75,7 @@ public class WindowsOffscreenWGLDrawable extends WindowsWGLDrawable {
   private void create() {
     NativeSurface ns = getNativeSurface();
     WindowsWGLGraphicsConfiguration config = (WindowsWGLGraphicsConfiguration)ns.getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities capabilities = (GLCapabilities)config.getRequestedCapabilities();
+    GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getRequestedCapabilities();
     int width = getWidth();
     int height = getHeight();
     BITMAPINFO info = BITMAPINFO.create();
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLContext.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLContext.java
index abbaf5004..db86b3232 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLContext.java
@@ -89,7 +89,7 @@ public class WindowsPbufferWGLContext extends WindowsWGLContext {
   protected void makeCurrentImpl(boolean newCreated) throws GLException {
     super.makeCurrentImpl(newCreated);
     if (newCreated) {
-      GLCapabilities capabilities = drawable.getChosenGLCapabilities();
+      GLCapabilitiesImmutable capabilities = drawable.getChosenGLCapabilities();
 
       // Initialize render-to-texture support if requested
       GL gl = getGL();
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLDrawable.java
index a5631aded..751ae5380 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsPbufferWGLDrawable.java
@@ -43,7 +43,6 @@ package com.jogamp.opengl.impl.windows.wgl;
 import javax.media.nativewindow.NativeSurface;
 import javax.media.nativewindow.SurfaceChangeable;
 import javax.media.opengl.GL;
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawableFactory;
 import javax.media.opengl.GLException;
@@ -52,6 +51,7 @@ import javax.media.opengl.GLProfile;
 
 import com.jogamp.nativewindow.impl.windows.GDI;
 import com.jogamp.nativewindow.impl.windows.PIXELFORMATDESCRIPTOR;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class WindowsPbufferWGLDrawable extends WindowsWGLDrawable {
   private WGLExt cachedWGLExt; // cached WGLExt instance from parent GLCanvas,
@@ -134,7 +134,7 @@ public class WindowsPbufferWGLDrawable extends WindowsWGLDrawable {
     int     width, height;
 
     WindowsWGLGraphicsConfiguration config = (WindowsWGLGraphicsConfiguration) getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities capabilities = (GLCapabilities)config.getRequestedCapabilities();
+    GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getRequestedCapabilities();
     GLProfile glProfile = capabilities.getGLProfile();
 
     if (DEBUG) {
@@ -302,7 +302,7 @@ public class WindowsPbufferWGLDrawable extends WindowsWGLDrawable {
       iattributes[niattribs++] = WGLExt.WGL_DRAW_TO_PBUFFER_ARB;
       int[] ivalues = new int[niattribs];
       if (wglExt.wglGetPixelFormatAttribivARB(parentHdc, pformats[whichFormat], 0, niattribs, iattributes, 0, ivalues, 0)) {
-        GLCapabilities newCaps = WindowsWGLGraphicsConfiguration.AttribList2GLCapabilities(glProfile, iattributes, niattribs, ivalues, true, false, true);
+        GLCapabilitiesImmutable newCaps = WindowsWGLGraphicsConfiguration.AttribList2GLCapabilities(glProfile, iattributes, niattribs, ivalues, true, false, true);
         PIXELFORMATDESCRIPTOR pfd = WindowsWGLGraphicsConfiguration.createPixelFormatDescriptor();
         if (GDI.DescribePixelFormat(parentHdc, pformats[whichFormat], pfd.size(), pfd) == 0) {
           if (DEBUG) {
@@ -318,7 +318,7 @@ public class WindowsPbufferWGLDrawable extends WindowsWGLDrawable {
         if (GDI.DescribePixelFormat(parentHdc, pformats[whichFormat], pfd.size(), pfd) == 0) {
           throw new GLException("Unable to describe pixel format " + pformats[whichFormat]);
         }
-        GLCapabilities newCaps = WindowsWGLGraphicsConfiguration.PFD2GLCapabilities(glProfile, pfd, false, true);
+        GLCapabilitiesImmutable newCaps = WindowsWGLGraphicsConfiguration.PFD2GLCapabilities(glProfile, pfd, false, true);
         if(newCaps.isOnscreen()) {
           throw new GLException("Error: Selected Onscreen Caps for PBuffer: "+newCaps+"\n\t"+newCaps);
         }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLContext.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLContext.java
index 529fda2c9..816532262 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLContext.java
@@ -46,7 +46,6 @@ import java.util.Map;
 
 import javax.media.nativewindow.AbstractGraphicsConfiguration;
 import javax.media.nativewindow.AbstractGraphicsDevice;
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLException;
 
@@ -56,6 +55,7 @@ import com.jogamp.nativewindow.impl.windows.GDI;
 import com.jogamp.opengl.impl.GLContextImpl;
 import com.jogamp.opengl.impl.GLContextShareSet;
 import com.jogamp.opengl.impl.GLDrawableImpl;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 
 public class WindowsWGLContext extends GLContextImpl {
@@ -232,7 +232,7 @@ public class WindowsWGLContext extends GLContextImpl {
     AbstractGraphicsConfiguration config = drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
     AbstractGraphicsDevice device = config.getScreen().getDevice();
     WindowsWGLContext sharedContext = (WindowsWGLContext) factory.getOrCreateSharedContextImpl(device);
-    GLCapabilities glCaps = drawable.getChosenGLCapabilities();
+    GLCapabilitiesImmutable glCaps = drawable.getChosenGLCapabilities();
 
     // Windows can set up sharing of display lists after creation time
     WindowsWGLContext other = (WindowsWGLContext) GLContextShareSet.getShareContext(this);
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLDrawableFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLDrawableFactory.java
index 462079913..51c5875cc 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLDrawableFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLDrawableFactory.java
@@ -55,7 +55,6 @@ import javax.media.nativewindow.DefaultGraphicsScreen;
 import javax.media.nativewindow.NativeSurface;
 import javax.media.nativewindow.NativeWindowFactory;
 import javax.media.nativewindow.windows.WindowsGraphicsDevice;
-import javax.media.opengl.GLCapabilities;
 import javax.media.opengl.GLCapabilitiesChooser;
 import javax.media.opengl.GLContext;
 import javax.media.opengl.GLDrawable;
@@ -66,11 +65,11 @@ import com.jogamp.common.JogampRuntimeException;
 import com.jogamp.common.util.ReflectionUtil;
 import com.jogamp.nativewindow.impl.ProxySurface;
 import com.jogamp.nativewindow.impl.windows.GDI;
-import com.jogamp.opengl.impl.Debug;
 import com.jogamp.opengl.impl.DesktopGLDynamicLookupHelper;
 import com.jogamp.opengl.impl.GLDrawableFactoryImpl;
 import com.jogamp.opengl.impl.GLDrawableImpl;
 import com.jogamp.opengl.impl.GLDynamicLookupHelper;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class WindowsWGLDrawableFactory extends GLDrawableFactoryImpl {
   private static final DesktopGLDynamicLookupHelper windowsWGLDynamicLookupHelper;
@@ -157,7 +156,7 @@ public class WindowsWGLDrawableFactory extends GLDrawableFactoryImpl {
         addDeviceTried(connection);
         NativeWindowFactory.getDefaultToolkitLock().lock(); // OK
         try {
-            WindowsDummyWGLDrawable sharedDrawable = new WindowsDummyWGLDrawable(this, null);
+            WindowsDummyWGLDrawable sharedDrawable = WindowsDummyWGLDrawable.create(this, null);
             WindowsWGLContext ctx  = (WindowsWGLContext) sharedDrawable.createContext(null);
             ctx.makeCurrent();
             boolean canCreateGLPbuffer = ctx.getGL().isExtensionAvailable("GL_ARB_pbuffer");
@@ -276,10 +275,10 @@ public class WindowsWGLDrawableFactory extends GLDrawableFactoryImpl {
     return (GLDrawableImpl) returnList.get(0);
   }
 
-  protected final NativeSurface createOffscreenSurfaceImpl(GLCapabilities capabilities, GLCapabilitiesChooser chooser, int width, int height) {
+  protected final NativeSurface createOffscreenSurfaceImpl(GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser, int width, int height) {
     AbstractGraphicsScreen screen = DefaultGraphicsScreen.createDefault(NativeWindowFactory.TYPE_WINDOWS);
     ProxySurface ns = new ProxySurface(WindowsWGLGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(
-                                     capabilities, chooser, screen) );
+                                     capsChosen, capsRequested, chooser, screen) );
     ns.setSize(width, height);
     return ns;
   }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfiguration.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfiguration.java
index 6c006577e..f714c7719 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfiguration.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfiguration.java
@@ -49,6 +49,7 @@ import javax.media.opengl.GLProfile;
 import com.jogamp.nativewindow.impl.windows.GDI;
 import com.jogamp.nativewindow.impl.windows.PIXELFORMATDESCRIPTOR;
 import com.jogamp.opengl.impl.GLContextImpl;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguration implements Cloneable {
     // Keep this under the same debug flag as the drawable factory for convenience
@@ -63,7 +64,8 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
     private GLCapabilitiesChooser chooser;
     private boolean choosenByWGLPixelFormat=false;
 
-    public WindowsWGLGraphicsConfiguration(AbstractGraphicsScreen screen, GLCapabilities capsChosen, GLCapabilities capsRequested,
+    public WindowsWGLGraphicsConfiguration(AbstractGraphicsScreen screen, 
+                                           GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested,
                                            PIXELFORMATDESCRIPTOR pixelfmt, int pixelfmtID, GLCapabilitiesChooser chooser) {
         super(screen, capsChosen, capsRequested);
         this.chooser=chooser;
@@ -85,7 +87,7 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
             throw new GLException("Unable to describe pixel format " + pfdID);
         }
 
-        GLCapabilities caps = PFD2GLCapabilities(glp, pfd, onscreen, usePBuffer);
+        GLCapabilitiesImmutable caps = PFD2GLCapabilities(glp, pfd, onscreen, usePBuffer);
         if(null==caps) {
             throw new GLException("Couldn't choose Capabilities by: HDC 0x"+Long.toHexString(hdc)+", pfdID "+pfdID);
         }
@@ -108,7 +110,7 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
     protected void updateCapabilitiesByWGL(GLContextImpl context) {
         if(choosenByWGLPixelFormat) return; // already done ..
 
-        GLCapabilities capabilities = (GLCapabilities) getRequestedCapabilities();
+        GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable) getRequestedCapabilities();
         boolean onscreen = capabilities.isOnscreen();
         boolean usePBuffer = capabilities.isPBuffer();
         GLProfile glp = capabilities.getGLProfile();
@@ -118,13 +120,13 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
         NativeSurface ns = drawable.getNativeSurface();
         long hdc = ns.getSurfaceHandle();
 
-        GLCapabilities[] caps = HDC2GLCapabilities(wglExt, hdc, getPixelFormatID(), glp, true, onscreen, usePBuffer);
+        GLCapabilitiesImmutable[] caps = HDC2GLCapabilities(wglExt, hdc, getPixelFormatID(), glp, true, onscreen, usePBuffer);
         if(null!=caps && null!=caps[0]) {
             setCapsPFD(caps[0], getPixelFormat(), getPixelFormatID(), true);
         }
     }
 
-    protected void setCapsPFD(GLCapabilities caps, PIXELFORMATDESCRIPTOR pfd, int pfdID, boolean choosenByWGLPixelFormat) {
+    protected void setCapsPFD(GLCapabilitiesImmutable caps, PIXELFORMATDESCRIPTOR pfd, int pfdID, boolean choosenByWGLPixelFormat) {
         this.pixelfmt = pfd;
         this.pixelfmtID = pfdID;
         setChosenCapabilities(caps);
@@ -146,8 +148,8 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
     private static int haveWGLChoosePixelFormatARB = -1;
     private static int haveWGLARBMultisample = -1;
 
-    public static GLCapabilities[] HDC2GLCapabilities(WGLExt wglExt, long hdc, int pfdIDOnly,
-                                                      GLProfile glp, boolean relaxed, boolean onscreen, boolean usePBuffer) {
+    public static GLCapabilitiesImmutable[] HDC2GLCapabilities(WGLExt wglExt, long hdc, int pfdIDOnly,
+                                                               GLProfile glp, boolean relaxed, boolean onscreen, boolean usePBuffer) {
     
         if(haveWGLChoosePixelFormatARB<0) {
             haveWGLChoosePixelFormatARB = wglExt.isExtensionAvailable("WGL_ARB_pixel_format")?1:0;
@@ -168,7 +170,7 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
         // "HardwareAccelerated" bit, which is basically
         // meaningless, and put in whether it can render to a
         // window, to a pbuffer, or to a pixmap)
-        GLCapabilities[] availableCaps = null;
+        GLCapabilitiesImmutable[] availableCaps = null;
         int numFormats = 0;
         int niattribs = 0;
         int[] iattributes = new int  [2*MAX_ATTRIBS];
@@ -212,14 +214,14 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
           }
 
           if(pfdIDOnly>0) {
-              availableCaps = new GLCapabilities[1];
+              availableCaps = new GLCapabilitiesImmutable[1];
               if (!wglExt.wglGetPixelFormatAttribivARB(hdc, pfdIDOnly, 0, niattribs, iattributes, 0, iresults, 0)) {
                   throw new GLException("Error getting pixel format attributes for pixel format " + pfdIDOnly + " of device context");
               }
               availableCaps[0] = AttribList2GLCapabilities(glp, iattributes, niattribs, iresults, 
                                                            relaxed, onscreen, usePBuffer);
           } else {
-              availableCaps = new GLCapabilities[numFormats];
+              availableCaps = new GLCapabilitiesImmutable[numFormats];
               for (int i = 0; i < numFormats; i++) {
                 if (!wglExt.wglGetPixelFormatAttribivARB(hdc, i+1, 0, niattribs, iattributes, 0, iresults, 0)) {
                   throw new GLException("Error getting pixel format attributes for pixel format " + (i + 1) + " of device context");
@@ -238,11 +240,11 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
         return availableCaps;
     }
 
-    public static boolean GLCapabilities2AttribList(GLCapabilities caps,
-                                                  int[] iattributes,
-                                                  WGLExt wglExt,
-                                                  boolean pbuffer,
-                                                  int[] floatMode) throws GLException {
+    public static boolean GLCapabilities2AttribList(GLCapabilitiesImmutable caps,
+                                                    int[] iattributes,
+                                                    WGLExt wglExt,
+                                                    boolean pbuffer,
+                                                    int[] floatMode) throws GLException {
         if (!wglExt.isExtensionAvailable("WGL_ARB_pixel_format")) {
           return false;
         }
@@ -436,7 +438,8 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
         return res;
     }
 
-    public static GLCapabilities AttribList2GLCapabilities(GLProfile glp, int[] iattribs,
+    public static GLCapabilitiesImmutable AttribList2GLCapabilities(
+                                                         GLProfile glp, int[] iattribs,
                                                          int niattribs,
                                                          int[] iresults,
                                                          boolean relaxed, boolean onscreen, boolean usePBuffer) {
@@ -552,7 +555,7 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
 
   // PIXELFORMAT
 
-    public static GLCapabilities PFD2GLCapabilities(GLProfile glp, PIXELFORMATDESCRIPTOR pfd, boolean onscreen, boolean usePBuffer) {
+    public static GLCapabilitiesImmutable PFD2GLCapabilities(GLProfile glp, PIXELFORMATDESCRIPTOR pfd, boolean onscreen, boolean usePBuffer) {
         if ((pfd.getDwFlags() & GDI.PFD_SUPPORT_OPENGL) == 0) {
           return null;
         }
@@ -586,7 +589,7 @@ public class WindowsWGLGraphicsConfiguration extends DefaultGraphicsConfiguratio
         return res;
   }
 
-  public static PIXELFORMATDESCRIPTOR GLCapabilities2PFD(GLCapabilities caps) {
+  public static PIXELFORMATDESCRIPTOR GLCapabilities2PFD(GLCapabilitiesImmutable caps) {
     int colorDepth = (caps.getRedBits() +
                       caps.getGreenBits() +
                       caps.getBlueBits());
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfigurationFactory.java
index 1d8f14d94..46b169343 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/WindowsWGLGraphicsConfigurationFactory.java
@@ -36,7 +36,6 @@ package com.jogamp.opengl.impl.windows.wgl;
 import javax.media.nativewindow.AbstractGraphicsConfiguration;
 import javax.media.nativewindow.AbstractGraphicsDevice;
 import javax.media.nativewindow.AbstractGraphicsScreen;
-import javax.media.nativewindow.Capabilities;
 import javax.media.nativewindow.CapabilitiesChooser;
 import javax.media.nativewindow.DefaultGraphicsScreen;
 import javax.media.nativewindow.GraphicsConfigurationFactory;
@@ -51,6 +50,8 @@ import javax.media.opengl.GLProfile;
 
 import com.jogamp.nativewindow.impl.windows.GDI;
 import com.jogamp.nativewindow.impl.windows.PIXELFORMATDESCRIPTOR;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 /** Subclass of GraphicsConfigurationFactory used when non-AWT tookits
     are used on Windows platforms. Toolkits will likely need to delegate
@@ -65,36 +66,44 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
-        GLCapabilities caps = (GLCapabilities)capabilities;
-        return chooseGraphicsConfigurationStatic(caps, chooser, absScreen);
-    }
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+
+        if (! (capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - chosen");
+        }
 
-    protected static WindowsWGLGraphicsConfiguration createDefaultGraphicsConfiguration(GLProfile glp, AbstractGraphicsScreen absScreen, boolean onscreen, boolean usePBuffer) {
-        GLCapabilities caps = new GLCapabilities(glp);
-        caps.setDoubleBuffered(onscreen); // FIXME DBLBUFOFFSCRN
-        caps.setOnscreen  (onscreen);
-        caps.setPBuffer   (usePBuffer);
+        if (! (capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - requested");
+        }
+
+        return chooseGraphicsConfigurationStatic((GLCapabilitiesImmutable)capsChosen, (GLCapabilitiesImmutable)capsRequested, chooser, absScreen);
+    }
 
+    protected static WindowsWGLGraphicsConfiguration createDefaultGraphicsConfiguration(GLCapabilitiesImmutable caps,
+                                                                                        AbstractGraphicsScreen absScreen) {
         if(null==absScreen) {
             absScreen = DefaultGraphicsScreen.createDefault(NativeWindowFactory.TYPE_WINDOWS);
         }
         return new WindowsWGLGraphicsConfiguration(absScreen, caps, caps, WindowsWGLGraphicsConfiguration.GLCapabilities2PFD(caps), -1, null);
-
     }
 
-    protected static WindowsWGLGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilities caps,
+    protected static WindowsWGLGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilitiesImmutable capsChosen,
+                                                                                       GLCapabilitiesImmutable capsReq,
                                                                                        CapabilitiesChooser chooser,
                                                                                        AbstractGraphicsScreen absScreen) {
         if(null==absScreen) {
             absScreen = DefaultGraphicsScreen.createDefault(NativeWindowFactory.TYPE_WINDOWS);
         }
-        GLCapabilities caps2 = (GLCapabilities) caps.clone();
-        if(!caps2.isOnscreen()) {
+
+        if(!capsChosen.isOnscreen() && capsChosen.getDoubleBuffered()) {
             // OFFSCREEN !DOUBLE_BUFFER // FIXME DBLBUFOFFSCRN
+            GLCapabilities caps2 = (GLCapabilities) capsChosen.cloneMutable();
             caps2.setDoubleBuffered(false);
+            capsChosen = caps2;
         }
-        return new WindowsWGLGraphicsConfiguration(absScreen, caps2, caps, WindowsWGLGraphicsConfiguration.GLCapabilities2PFD(caps2), -1, 
+
+        return new WindowsWGLGraphicsConfiguration(absScreen, capsChosen, capsReq,
+                                                   WindowsWGLGraphicsConfiguration.GLCapabilities2PFD(capsChosen), -1,
                                                    (GLCapabilitiesChooser)chooser);
     }
 
@@ -117,7 +126,7 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
             throw new InternalError("SharedContext is null: "+device);
         }
         boolean choosenBywGLPixelFormat = false;
-        GLCapabilities capabilities = (GLCapabilities) config.getRequestedCapabilities();
+        GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable) config.getChosenCapabilities();
         boolean onscreen = capabilities.isOnscreen();
         boolean usePBuffer = capabilities.isPBuffer();
         GLProfile glProfile = capabilities.getGLProfile();
@@ -134,7 +143,7 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
         PIXELFORMATDESCRIPTOR pfd = null;
         int pixelFormat = -1; // 1-based pixel format
         boolean pixelFormatSet = false;
-        GLCapabilities chosenCaps = null;
+        GLCapabilitiesImmutable chosenCaps = null;
 
         if (onscreen) {
           if ((pixelFormat = GDI.GetPixelFormat(hdc)) != 0) {
@@ -149,7 +158,7 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
             pixelFormatSet = true;
           }
 
-          GLCapabilities[] availableCaps = null;
+          GLCapabilitiesImmutable[] availableCaps = null;
           int numFormats = 0;
           pfd = WindowsWGLGraphicsConfiguration.createPixelFormatDescriptor();
           // Produce a recommended pixel format selection for the GLCapabilitiesChooser.
@@ -234,7 +243,7 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
               throw new GLException("Unable to enumerate pixel formats of window " +
                                     toHexString(hdc) + " for GLCapabilitiesChooser (LastError: "+GDI.GetLastError()+")");
             }
-            availableCaps = new GLCapabilities[numFormats];
+            availableCaps = new GLCapabilitiesImmutable[numFormats];
             for (int i = 0; i < numFormats; i++) {
               if (GDI.DescribePixelFormat(hdc, 1 + i, pfd.size(), pfd) == 0) {
                 throw new GLException("Error describing pixel format " + (1 + i) + " of device context");
@@ -255,7 +264,7 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
                     pixelFormat = chooser.chooseCapabilities(capabilities, availableCaps, recommendedPixelFormat) + 1;
                   } catch (NativeWindowException e) {
                     if(DEBUG) {
-                          e.printStackTrace();
+                        e.printStackTrace();
                     }
                     pixelFormat = -1;
                   }
@@ -315,11 +324,12 @@ public class WindowsWGLGraphicsConfigurationFactory extends GraphicsConfiguratio
         config.setCapsPFD(capabilities, pfd, pixelFormat, choosenBywGLPixelFormat);
     }
 
-  protected static String getThreadName() {
-    return Thread.currentThread().getName();
-  }
-  public static String toHexString(long hex) {
-      return "0x" + Long.toHexString(hex);
-  }
+    protected static String getThreadName() {
+        return Thread.currentThread().getName();
+    }
+
+    public static String toHexString(long hex) {
+        return "0x" + Long.toHexString(hex);
+    }
 }
 
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/awt/WindowsAWTWGLGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/awt/WindowsAWTWGLGraphicsConfigurationFactory.java
index 48850440d..363881ef0 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/awt/WindowsAWTWGLGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/windows/wgl/awt/WindowsAWTWGLGraphicsConfigurationFactory.java
@@ -32,19 +32,27 @@
 
 package com.jogamp.opengl.impl.windows.wgl.awt;
 
+
 import java.awt.GraphicsConfiguration;
 import java.awt.GraphicsDevice;
-import java.awt.GraphicsEnvironment;
-import javax.media.nativewindow.*;
-import javax.media.nativewindow.windows.*;
-import javax.media.nativewindow.awt.*;
-import javax.media.opengl.*;
-import javax.media.opengl.awt.*;
-
-import com.jogamp.opengl.impl.*;
-import com.jogamp.opengl.impl.windows.wgl.*;
-import com.jogamp.nativewindow.impl.jawt.*;
-import com.jogamp.nativewindow.impl.jawt.windows.*;
+
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.AbstractGraphicsDevice;
+import javax.media.nativewindow.AbstractGraphicsScreen;
+import javax.media.nativewindow.CapabilitiesChooser;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.nativewindow.DefaultGraphicsScreen;
+import javax.media.nativewindow.GraphicsConfigurationFactory;
+import javax.media.nativewindow.awt.AWTGraphicsConfiguration;
+import javax.media.nativewindow.awt.AWTGraphicsDevice;
+import javax.media.nativewindow.awt.AWTGraphicsScreen;
+import javax.media.nativewindow.windows.WindowsGraphicsDevice;
+
+import javax.media.opengl.GLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLException;
+
+import com.jogamp.opengl.impl.windows.wgl.WindowsWGLGraphicsConfiguration;
 
 public class WindowsAWTWGLGraphicsConfigurationFactory extends GraphicsConfigurationFactory {
     protected static final boolean DEBUG = com.jogamp.opengl.impl.Debug.debug("GraphicsConfiguration");
@@ -54,7 +62,8 @@ public class WindowsAWTWGLGraphicsConfigurationFactory extends GraphicsConfigura
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+            CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
         GraphicsDevice device = null;
         if (absScreen != null &&
             !(absScreen instanceof AWTGraphicsScreen)) {
@@ -67,9 +76,12 @@ public class WindowsAWTWGLGraphicsConfigurationFactory extends GraphicsConfigura
         AWTGraphicsScreen awtScreen = (AWTGraphicsScreen) absScreen;
         device = ((AWTGraphicsDevice)awtScreen.getDevice()).getGraphicsDevice();
 
-        if (capabilities != null &&
-            !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects");
+        if ( !(capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if ( !(capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null &&
@@ -81,13 +93,11 @@ public class WindowsAWTWGLGraphicsConfigurationFactory extends GraphicsConfigura
             System.err.println("WindowsAWTWGLGraphicsConfigurationFactory: got "+absScreen);
         }
         GraphicsConfiguration gc = device.getDefaultConfiguration();
-        AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capabilities, gc);
+        capsChosen = AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capsChosen, gc);
         if(DEBUG) {
-            System.err.println("AWT Colormodel compatible: "+capabilities);
+            System.err.println("AWT Colormodel compatible: "+capsChosen);
         }
 
-        long displayHandle = 0;
-
         WindowsGraphicsDevice winDevice = new WindowsGraphicsDevice(AbstractGraphicsDevice.DEFAULT_UNIT);
         DefaultGraphicsScreen winScreen = new DefaultGraphicsScreen(winDevice, awtScreen.getIndex());
         if(DEBUG) {
@@ -95,12 +105,12 @@ public class WindowsAWTWGLGraphicsConfigurationFactory extends GraphicsConfigura
         }
 
         WindowsWGLGraphicsConfiguration winConfig = (WindowsWGLGraphicsConfiguration)
-            GraphicsConfigurationFactory.getFactory(winDevice).chooseGraphicsConfiguration(capabilities,
-                                                                                           chooser,
-                                                                                           winScreen);
+            GraphicsConfigurationFactory.getFactory(winDevice).chooseGraphicsConfiguration(capsChosen,
+                                                                                           capsRequested,
+                                                                                           chooser, winScreen);
 
         if (winConfig == null) {
-            throw new GLException("Unable to choose a GraphicsConfiguration: "+capabilities+",\n\t"+chooser+"\n\t"+winScreen);
+            throw new GLException("Unable to choose a GraphicsConfiguration: "+capsChosen+",\n\t"+chooser+"\n\t"+winScreen);
         }
 
         if(DEBUG) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11DummyGLXDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11DummyGLXDrawable.java
index e77735637..6c8d1fc91 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11DummyGLXDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11DummyGLXDrawable.java
@@ -43,10 +43,10 @@ public class X11DummyGLXDrawable extends X11OnscreenGLXDrawable {
    * we cannot switch the Display as we please, 
    * hence we reuse the target's screen configuration. 
    */
-  public X11DummyGLXDrawable(X11GraphicsScreen screen, GLDrawableFactory factory, GLProfile glp) {
+  public X11DummyGLXDrawable(X11GraphicsScreen screen, GLDrawableFactory factory, GLCapabilitiesImmutable caps) {
     super(factory, 
           new ProxySurface(X11GLXGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(
-            new GLCapabilities(glp), null, screen)));
+            caps, caps, null, screen)));
     this.realized = true;
 
     ProxySurface ns = (ProxySurface) getNativeSurface();
@@ -63,6 +63,11 @@ public class X11DummyGLXDrawable extends X11OnscreenGLXDrawable {
     updateHandle();
   }
 
+  public static X11DummyGLXDrawable create(X11GraphicsScreen screen, GLDrawableFactory factory, GLProfile glp) {
+      GLCapabilities caps = new GLCapabilities(glp);
+      return new X11DummyGLXDrawable(screen, factory, caps);
+  }
+
   public void setSize(int width, int height) {
   }
 
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXContext.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXContext.java
index 63b758da3..1dadc2edf 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXContext.java
@@ -268,7 +268,7 @@ public abstract class X11GLXContext extends GLContextImpl {
       direct = GLX.glXIsDirect(display, share);
     }
 
-    GLCapabilities glCaps = (GLCapabilities) config.getChosenCapabilities();
+    GLCapabilitiesImmutable glCaps = (GLCapabilitiesImmutable) config.getChosenCapabilities();
     GLProfile glp = glCaps.getGLProfile();
     isVendorATI = factory.isVendorATI(device);
 
@@ -494,7 +494,7 @@ public abstract class X11GLXContext extends GLContextImpl {
 
   protected void setSwapIntervalImpl(int interval) {
     X11GLXGraphicsConfiguration config = (X11GLXGraphicsConfiguration)drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration();
-    GLCapabilities glCaps = (GLCapabilities) config.getChosenCapabilities();
+    GLCapabilitiesImmutable glCaps = (GLCapabilitiesImmutable) config.getChosenCapabilities();
     if(!glCaps.isOnscreen()) return;
 
     GLXExt glXExt = getGLXExt();
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXDrawableFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXDrawableFactory.java
index d98d8a436..d4df76315 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXDrawableFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXDrawableFactory.java
@@ -210,7 +210,8 @@ public class X11GLXDrawableFactory extends GLDrawableFactoryImpl {
           try {
               String vendorName = GLXUtil.getVendorName(sharedDevice.getHandle());
               X11GraphicsScreen sharedScreen = new X11GraphicsScreen(sharedDevice, 0);
-              X11DummyGLXDrawable sharedDrawable = new X11DummyGLXDrawable(sharedScreen, X11GLXDrawableFactory.this, GLProfile.getDefault(sharedDevice));
+              X11DummyGLXDrawable sharedDrawable = X11DummyGLXDrawable.create(sharedScreen, X11GLXDrawableFactory.this,
+                                                                              GLProfile.getDefault(sharedDevice));
               if (null == sharedScreen || null == sharedDrawable) {
                   throw new GLException("Couldn't init shared screen(" + sharedScreen + ")/drawable(" + sharedDrawable + ")");
               }
@@ -482,7 +483,8 @@ public class X11GLXDrawableFactory extends GLDrawableFactoryImpl {
   }
 
 
-  protected final NativeSurface createOffscreenSurfaceImpl(GLCapabilities capabilities, GLCapabilitiesChooser chooser, int width, int height) {
+  protected final NativeSurface createOffscreenSurfaceImpl(GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser,
+                                                           int width, int height) {
     X11GraphicsScreen screen = null;
     SharedResource sr = getOrCreateShared(defaultDevice);
     if(null!=sr) {
@@ -493,7 +495,7 @@ public class X11GLXDrawableFactory extends GLDrawableFactoryImpl {
     }
 
     ProxySurface ns = new ProxySurface(
-               X11GLXGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(capabilities, chooser, screen) );
+               X11GLXGraphicsConfigurationFactory.chooseGraphicsConfigurationStatic(capsChosen, capsRequested, chooser, screen) );
     if(ns != null) {
         ns.setSize(width, height);
     }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfiguration.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfiguration.java
index b2bc59578..9cb00b198 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfiguration.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfiguration.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -48,7 +49,7 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
     private GLCapabilitiesChooser chooser; 
 
     public X11GLXGraphicsConfiguration(X11GraphicsScreen screen, 
-                                       GLCapabilities capsChosen, GLCapabilities capsRequested, GLCapabilitiesChooser chooser,
+                                       GLCapabilitiesImmutable capsChosen, GLCapabilitiesImmutable capsRequested, GLCapabilitiesChooser chooser,
                                        XVisualInfo info, long fbcfg, int fbcfgID) {
         super(screen, capsChosen, capsRequested, info);
         this.chooser=chooser;
@@ -69,7 +70,7 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
       if(null==glp) {
         glp = GLProfile.getDefault(x11Screen.getDevice());
       }
-      GLCapabilities caps = GLXFBConfig2GLCapabilities(glp, display, fbcfg, true, true, true, GLXUtil.isMultisampleAvailable(display));
+      GLCapabilitiesImmutable caps = GLXFBConfig2GLCapabilities(glp, display, fbcfg, true, true, true, GLXUtil.isMultisampleAvailable(display));
       if(null==caps) {
           throw new GLException("GLCapabilities null of "+toHexString(fbcfg));
       }
@@ -89,9 +90,8 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
 
     protected void updateGraphicsConfiguration() {
         X11GLXGraphicsConfiguration newConfig = (X11GLXGraphicsConfiguration)
-            GraphicsConfigurationFactory.getFactory(getScreen().getDevice()).chooseGraphicsConfiguration(getRequestedCapabilities().cloneCapabilites(),
-                                                                                                         chooser,
-                                                                                                         getScreen());
+            GraphicsConfigurationFactory.getFactory(getScreen().getDevice()).chooseGraphicsConfiguration(
+                getChosenCapabilities(), getRequestedCapabilities(), chooser, getScreen());
         if(null!=newConfig) {
             // FIXME: setScreen( ... );
             setXVisualInfo(newConfig.getXVisualInfo());
@@ -108,7 +108,7 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
         return value != 0 ? value : (int)GLX.GLX_DONT_CARE ;
     }
 
-    public static int[] GLCapabilities2AttribList(GLCapabilities caps,
+    public static int[] GLCapabilities2AttribList(GLCapabilitiesImmutable caps,
                                                   boolean forFBAttr,
                                                   boolean isMultisampleAvailable,
                                                   long display,
@@ -236,8 +236,9 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
     return res;
   }
 
-  public static GLCapabilities GLXFBConfig2GLCapabilities(GLProfile glp, long display, long fbcfg, 
-                                                          boolean relaxed, boolean onscreen, boolean usePBuffer, boolean isMultisampleEnabled) {
+  public static GLCapabilitiesImmutable GLXFBConfig2GLCapabilities(GLProfile glp, long display, long fbcfg,
+                                                                   boolean relaxed, boolean onscreen, boolean usePBuffer,
+                                                                   boolean isMultisampleEnabled) {
     int[] tmp = new int[1];
     int val;
     val = glXGetFBConfig(display, fbcfg, GLX.GLX_RENDER_TYPE, tmp, 0);
@@ -351,7 +352,8 @@ public class X11GLXGraphicsConfiguration extends X11GraphicsConfiguration implem
       return res;
   }
 
-  public static GLCapabilities XVisualInfo2GLCapabilities(GLProfile glp, long display, XVisualInfo info, boolean onscreen, boolean usePBuffer, boolean isMultisampleEnabled) {
+  public static GLCapabilitiesImmutable XVisualInfo2GLCapabilities(GLProfile glp, long display, XVisualInfo info,
+                                                                   boolean onscreen, boolean usePBuffer, boolean isMultisampleEnabled) {
     int[] tmp = new int[1];
     int val = glXGetConfig(display, info, GLX.GLX_USE_GL, tmp, 0);
     if (val == 0) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfigurationFactory.java
index 8dbd69dce..1b20040b0 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11GLXGraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -32,13 +33,26 @@
 
 package com.jogamp.opengl.impl.x11.glx;
 
-import com.jogamp.common.nio.PointerBuffer;
-import javax.media.nativewindow.*;
-import javax.media.nativewindow.x11.*;
-import com.jogamp.nativewindow.impl.x11.*;
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.AbstractGraphicsDevice;
+import javax.media.nativewindow.AbstractGraphicsScreen;
+import javax.media.nativewindow.CapabilitiesChooser;
+import javax.media.nativewindow.CapabilitiesImmutable;
+import javax.media.nativewindow.GraphicsConfigurationFactory;
+import javax.media.nativewindow.NativeWindowException;
+import javax.media.nativewindow.x11.X11GraphicsScreen;
+import javax.media.opengl.DefaultGLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilities;
+import javax.media.opengl.GLCapabilitiesChooser;
+import javax.media.opengl.GLCapabilitiesImmutable;
+import javax.media.opengl.GLException;
+import javax.media.opengl.GLProfile;
 
-import javax.media.opengl.*;
-import com.jogamp.opengl.impl.*;
+import com.jogamp.common.nio.PointerBuffer;
+import com.jogamp.nativewindow.impl.x11.X11Lib;
+import com.jogamp.nativewindow.impl.x11.X11Util;
+import com.jogamp.nativewindow.impl.x11.XVisualInfo;
+import com.jogamp.opengl.impl.Debug;
 
 
 /** Subclass of GraphicsConfigurationFactory used when non-AWT toolkits
@@ -54,19 +68,24 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
         if (!(absScreen instanceof X11GraphicsScreen)) {
             throw new IllegalArgumentException("Only X11GraphicsScreen are allowed here");
         }
 
-        if (capabilities != null && !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects");
+        if ( !(capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if ( !(capsRequested instanceof GLCapabilitiesImmutable)) {
+            throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null && !(chooser instanceof GLCapabilitiesChooser)) {
             throw new IllegalArgumentException("This NativeWindowFactory accepts only GLCapabilitiesChooser objects");
         }
-        return chooseGraphicsConfigurationStatic((GLCapabilities)capabilities, (GLCapabilitiesChooser)chooser, (X11GraphicsScreen)absScreen);
+        return chooseGraphicsConfigurationStatic((GLCapabilitiesImmutable)capsChosen, (GLCapabilitiesImmutable)capsRequested,
+                                                 (GLCapabilitiesChooser)chooser, (X11GraphicsScreen)absScreen);
     }
 
     /**
@@ -119,56 +138,58 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
       return new X11GLXGraphicsConfiguration(x11Screen, (null!=capsFB)?capsFB:caps, caps, null, xvis, fbcfg, fbid);
     } */
 
-    protected static X11GLXGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilities capabilities,
-                                                                                  GLCapabilitiesChooser chooser,
-                                                                                  X11GraphicsScreen x11Screen) {
+    protected static X11GLXGraphicsConfiguration chooseGraphicsConfigurationStatic(GLCapabilitiesImmutable capsChosen,
+                                                                                   GLCapabilitiesImmutable capsReq,
+                                                                                   GLCapabilitiesChooser chooser,
+                                                                                   X11GraphicsScreen x11Screen) {
         if (x11Screen == null) {
             throw new IllegalArgumentException("AbstractGraphicsScreen is null");
         }
 
-        if (capabilities == null) {
-            capabilities = new GLCapabilities(null);
+        if (capsChosen == null) {
+            capsChosen = new GLCapabilities(null);
         }
 
-        GLCapabilities caps2 = (GLCapabilities) capabilities.clone();
-
-        boolean usePBuffer = caps2.isPBuffer();
-
-        if(!caps2.isOnscreen()) {
+        if(!capsChosen.isOnscreen() && capsChosen.getDoubleBuffered()) {
             // OFFSCREEN !DOUBLE_BUFFER // FIXME DBLBUFOFFSCRN
+            GLCapabilities caps2 = (GLCapabilities) capsChosen.cloneMutable();
             caps2.setDoubleBuffered(false);
+            capsChosen = caps2;
         }
+
+        boolean usePBuffer = capsChosen.isPBuffer();
     
         X11GLXGraphicsConfiguration res;
-        res = chooseGraphicsConfigurationFBConfig(caps2, chooser, x11Screen);
+        res = chooseGraphicsConfigurationFBConfig(capsChosen, capsReq, chooser, x11Screen);
         if(null==res) {
             if(usePBuffer) {
-                throw new GLException("Error: Couldn't create X11GLXGraphicsConfiguration based on FBConfig for "+caps2);
+                throw new GLException("Error: Couldn't create X11GLXGraphicsConfiguration based on FBConfig for "+capsChosen);
             }
-            res = chooseGraphicsConfigurationXVisual(caps2, chooser, x11Screen);
+            res = chooseGraphicsConfigurationXVisual(capsChosen, capsReq, chooser, x11Screen);
         }
         if(null==res) {
-            throw new GLException("Error: Couldn't create X11GLXGraphicsConfiguration based on FBConfig and XVisual for "+caps2);
+            throw new GLException("Error: Couldn't create X11GLXGraphicsConfiguration based on FBConfig and XVisual for "+capsChosen);
         }
         if(DEBUG) {
-            System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationStatic("+x11Screen+","+caps2+"): "+res);
+            System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationStatic("+x11Screen+","+capsChosen+"): "+res);
         }
         return res;
     }
 
-    private static X11GLXGraphicsConfiguration chooseGraphicsConfigurationFBConfig(GLCapabilities capabilities,
-                                                                                     GLCapabilitiesChooser chooser,
-                                                                                     X11GraphicsScreen x11Screen) {
+    private static X11GLXGraphicsConfiguration chooseGraphicsConfigurationFBConfig(GLCapabilitiesImmutable capsChosen,
+                                                                                   GLCapabilitiesImmutable capsReq,
+                                                                                   GLCapabilitiesChooser chooser,
+                                                                                   X11GraphicsScreen x11Screen) {
         long recommendedFBConfig = 0;
         int recommendedIndex = -1;
-        GLCapabilities[] caps = null;
+        GLCapabilitiesImmutable[] caps = null;
         PointerBuffer fbcfgsL = null;
         int chosen=-1;
         int retFBID=-1;
         XVisualInfo retXVisualInfo = null;
-        GLProfile glProfile = capabilities.getGLProfile();
-        boolean onscreen = capabilities.isOnscreen();
-        boolean usePBuffer = capabilities.isPBuffer();
+        GLProfile glProfile = capsChosen.getGLProfile();
+        boolean onscreen = capsChosen.isOnscreen();
+        boolean usePBuffer = capsChosen.isPBuffer();
 
         // Utilizing FBConfig
         //
@@ -177,18 +198,18 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
 
         int screen = x11Screen.getIndex();
         boolean isMultisampleAvailable = GLXUtil.isMultisampleAvailable(display);
-        int[] attribs = X11GLXGraphicsConfiguration.GLCapabilities2AttribList(capabilities, true, isMultisampleAvailable, display, screen);
+        int[] attribs = X11GLXGraphicsConfiguration.GLCapabilities2AttribList(capsChosen, true, isMultisampleAvailable, display, screen);
         int[] count = { -1 };
 
         // determine the recommended FBConfig ..
         fbcfgsL = GLX.glXChooseFBConfig(display, screen, attribs, 0, count, 0);
         if (fbcfgsL == null || fbcfgsL.limit()<1) {
             if(DEBUG) {
-                System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: Failed glXChooseFBConfig ("+x11Screen+","+capabilities+"): "+fbcfgsL+", "+count[0]);
+                System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: Failed glXChooseFBConfig ("+x11Screen+","+capsChosen+"): "+fbcfgsL+", "+count[0]);
             }
         } else if( !X11GLXGraphicsConfiguration.GLXFBConfigValid( display, fbcfgsL.get(0) ) ) {
             if(DEBUG) {
-                System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: Failed - GLX FBConfig invalid: ("+x11Screen+","+capabilities+"): "+fbcfgsL+", fbcfg: "+toHexString(fbcfgsL.get(0)));
+                System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: Failed - GLX FBConfig invalid: ("+x11Screen+","+capsChosen+"): "+fbcfgsL+", fbcfg: "+toHexString(fbcfgsL.get(0)));
             }
         } else {
             recommendedFBConfig = fbcfgsL.get(0);
@@ -204,11 +225,11 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
         }
 
         // make GLCapabilities and seek the recommendedIndex
-        caps = new GLCapabilities[fbcfgsL.limit()];
+        caps = new GLCapabilitiesImmutable[fbcfgsL.limit()];
         for (int i = 0; i < fbcfgsL.limit(); i++) {
             if( !X11GLXGraphicsConfiguration.GLXFBConfigValid( display, fbcfgsL.get(i) ) ) {
                 if(DEBUG) {
-                    System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: FBConfig invalid: ("+x11Screen+","+capabilities+"): fbcfg: "+toHexString(fbcfgsL.get(i)));
+                    System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig: FBConfig invalid: ("+x11Screen+","+capsChosen+"): fbcfg: "+toHexString(fbcfgsL.get(i)));
                 }
             } else {
                 caps[i] = X11GLXGraphicsConfiguration.GLXFBConfig2GLCapabilities(glProfile, display, fbcfgsL.get(i),
@@ -232,7 +253,7 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
                 chooser = new DefaultGLCapabilitiesChooser();
             }
             try {
-              chosen = chooser.chooseCapabilities(capabilities, caps, recommendedIndex);
+              chosen = chooser.chooseCapabilities(capsChosen, caps, recommendedIndex);
             } catch (NativeWindowException e) {
               if(DEBUG) {
                   e.printStackTrace();
@@ -246,7 +267,9 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
               System.err.println("X11GLXGraphicsConfiguration.chooseGraphicsConfigurationFBConfig Failed .. unable to choose config, using first");
           }
           // seek first available one ..
-          for(chosen = 0; chosen < caps.length && caps[chosen]==null; chosen++) ;
+          for(chosen = 0; chosen < caps.length && caps[chosen]==null; chosen++) {
+              // nop
+          }
           if(chosen==caps.length) {
             // give up ..
             if(DEBUG) {
@@ -274,12 +297,13 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
             }
         }
 
-        return new X11GLXGraphicsConfiguration(x11Screen, caps[chosen], capabilities, chooser, retXVisualInfo, fbcfgsL.get(chosen), retFBID);
+        return new X11GLXGraphicsConfiguration(x11Screen, caps[chosen], capsReq, chooser, retXVisualInfo, fbcfgsL.get(chosen), retFBID);
     }
 
-    private static X11GLXGraphicsConfiguration chooseGraphicsConfigurationXVisual(GLCapabilities capabilities,
-                                                                                    GLCapabilitiesChooser chooser,
-                                                                                    X11GraphicsScreen x11Screen) {
+    private static X11GLXGraphicsConfiguration chooseGraphicsConfigurationXVisual(GLCapabilitiesImmutable capsChosen,
+                                                                                  GLCapabilitiesImmutable capsReq,
+                                                                                  GLCapabilitiesChooser chooser,
+                                                                                  X11GraphicsScreen x11Screen) {
         if (chooser == null) {
             chooser = new DefaultGLCapabilitiesChooser();
         }
@@ -288,9 +312,9 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
         // in pure Java, we're going to provide the underlying window
         // system's selection to the chooser as a hint
 
-        GLProfile glProfile = capabilities.getGLProfile();
-        boolean onscreen = capabilities.isOnscreen();
-        GLCapabilities[] caps = null;
+        GLProfile glProfile = capsChosen.getGLProfile();
+        boolean onscreen = capsChosen.isOnscreen();
+        GLCapabilitiesImmutable[] caps = null;
         int recommendedIndex = -1;
         XVisualInfo retXVisualInfo = null;
         int chosen=-1;
@@ -300,7 +324,7 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
 
         int screen = x11Screen.getIndex();
         boolean isMultisampleAvailable = GLXUtil.isMultisampleAvailable(display);
-        int[] attribs = X11GLXGraphicsConfiguration.GLCapabilities2AttribList(capabilities, false, isMultisampleAvailable, display, screen);
+        int[] attribs = X11GLXGraphicsConfiguration.GLCapabilities2AttribList(capsChosen, false, isMultisampleAvailable, display, screen);
         XVisualInfo[] infos = null;
 
         XVisualInfo recommendedVis = GLX.glXChooseVisual(display, screen, attribs, 0);
@@ -319,7 +343,7 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
         if (infos == null || infos.length<1) {
             throw new GLException("Error while enumerating available XVisualInfos");
         }
-        caps = new GLCapabilities[infos.length];
+        caps = new GLCapabilitiesImmutable[infos.length];
         for (int i = 0; i < infos.length; i++) {
             caps[i] = X11GLXGraphicsConfiguration.XVisualInfo2GLCapabilities(glProfile, display, infos[i], onscreen, false, isMultisampleAvailable);
             // Attempt to find the visual chosen by glXChooseVisual
@@ -328,7 +352,7 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
             }
         }
         try {
-          chosen = chooser.chooseCapabilities(capabilities, caps, recommendedIndex);
+          chosen = chooser.chooseCapabilities(capsChosen, caps, recommendedIndex);
         } catch (NativeWindowException e) {
           if(DEBUG) {
               e.printStackTrace();
@@ -348,7 +372,7 @@ public class X11GLXGraphicsConfigurationFactory extends GraphicsConfigurationFac
             throw new GLException("GLCapabilitiesChooser chose an invalid visual for "+caps[chosen]);
         }
         retXVisualInfo = XVisualInfo.create(infos[chosen]);
-        return new X11GLXGraphicsConfiguration(x11Screen, caps[chosen], capabilities, chooser, retXVisualInfo, 0, -1);
+        return new X11GLXGraphicsConfiguration(x11Screen, caps[chosen], capsReq, chooser, retXVisualInfo, 0, -1);
     }
 
     public static String toHexString(int val) {
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11OffscreenGLXContext.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11OffscreenGLXContext.java
index 7054faa0c..5ae641278 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11OffscreenGLXContext.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11OffscreenGLXContext.java
@@ -55,7 +55,7 @@ public class X11OffscreenGLXContext extends X11GLXContext {
   }
   
   public int getOffscreenContextReadBuffer() {
-    GLCapabilities caps = (GLCapabilities)drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
+    GLCapabilitiesImmutable caps = (GLCapabilitiesImmutable)drawable.getNativeSurface().getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
     if (caps.getDoubleBuffered()) {
       return GL.GL_BACK;
     }
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11PbufferGLXDrawable.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11PbufferGLXDrawable.java
index b86394cc6..41cd543aa 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11PbufferGLXDrawable.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/X11PbufferGLXDrawable.java
@@ -94,7 +94,7 @@ public class X11PbufferGLXDrawable extends X11GLXDrawable {
 
       NativeSurface ns = getNativeSurface();
     
-      GLCapabilities capabilities = (GLCapabilities)config.getChosenCapabilities();
+      GLCapabilitiesImmutable capabilities = (GLCapabilitiesImmutable)config.getChosenCapabilities();
 
       if (capabilities.getPbufferRenderToTexture()) {
         throw new GLException("Render-to-texture pbuffers not supported yet on X11");
diff --git a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/awt/X11AWTGLXGraphicsConfigurationFactory.java b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/awt/X11AWTGLXGraphicsConfigurationFactory.java
index d4af56aca..03955b439 100644
--- a/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/awt/X11AWTGLXGraphicsConfigurationFactory.java
+++ b/src/jogl/classes/com/jogamp/opengl/impl/x11/glx/awt/X11AWTGLXGraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -51,7 +52,8 @@ public class X11AWTGLXGraphicsConfigurationFactory extends GraphicsConfiguration
     }
 
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+            CapabilitiesChooser chooser, AbstractGraphicsScreen absScreen) {
         GraphicsDevice device = null;
         if (absScreen != null &&
             !(absScreen instanceof AWTGraphicsScreen)) {
@@ -64,9 +66,12 @@ public class X11AWTGLXGraphicsConfigurationFactory extends GraphicsConfiguration
         AWTGraphicsScreen awtScreen = (AWTGraphicsScreen) absScreen;
         device = ((AWTGraphicsDevice)awtScreen.getDevice()).getGraphicsDevice();
 
-        if (capabilities != null &&
-            !(capabilities instanceof GLCapabilities)) {
-            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects");
+        if ( !(capsChosen instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - chosen");
+        }
+
+        if ( !(capsRequested instanceof GLCapabilitiesImmutable) ) {
+            throw new IllegalArgumentException("This GraphicsConfigurationFactory accepts only GLCapabilities objects - requested");
         }
 
         if (chooser != null &&
@@ -103,14 +108,14 @@ public class X11AWTGLXGraphicsConfigurationFactory extends GraphicsConfiguration
         }
 
         gc = device.getDefaultConfiguration();
-        AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capabilities, gc);
+        capsChosen = AWTGraphicsConfiguration.setupCapabilitiesRGBABits(capsChosen, gc);
         if(DEBUG) {
-            System.err.println("AWT Colormodel compatible: "+capabilities);
+            System.err.println("AWT Colormodel compatible: "+capsChosen);
         }
         GraphicsConfigurationFactory factory = GraphicsConfigurationFactory.getFactory(x11Device);
-        x11Config = (X11GraphicsConfiguration)factory.chooseGraphicsConfiguration(capabilities, chooser, x11Screen);
+        x11Config = (X11GraphicsConfiguration)factory.chooseGraphicsConfiguration(capsChosen, capsRequested, chooser, x11Screen);
         if (x11Config == null) {
-            throw new GLException("Unable to choose a GraphicsConfiguration: "+capabilities+",\n\t"+chooser+"\n\t"+x11Screen);
+            throw new GLException("Unable to choose a GraphicsConfiguration: "+capsChosen+",\n\t"+chooser+"\n\t"+x11Screen);
         }
 
         long visualID = x11Config.getVisualID();
diff --git a/src/jogl/classes/javax/media/opengl/DefaultGLCapabilitiesChooser.java b/src/jogl/classes/javax/media/opengl/DefaultGLCapabilitiesChooser.java
index dc6daa645..695fad5a9 100644
--- a/src/jogl/classes/javax/media/opengl/DefaultGLCapabilitiesChooser.java
+++ b/src/jogl/classes/javax/media/opengl/DefaultGLCapabilitiesChooser.java
@@ -40,9 +40,9 @@
 
 package javax.media.opengl;
 
-import javax.media.nativewindow.Capabilities;
 import javax.media.nativewindow.NativeWindowException;
 import com.jogamp.opengl.impl.Debug;
+import javax.media.nativewindow.CapabilitiesImmutable;
 
 /** <P> The default implementation of the {@link
     GLCapabilitiesChooser} interface, which provides consistent visual
@@ -85,11 +85,11 @@ import com.jogamp.opengl.impl.Debug;
 public class DefaultGLCapabilitiesChooser implements GLCapabilitiesChooser {
   private static final boolean DEBUG = Debug.debug("CapabilitiesChooser");
 
-  public int chooseCapabilities(Capabilities desired,
-                                Capabilities[] available,
+  public int chooseCapabilities(CapabilitiesImmutable desired,
+                                CapabilitiesImmutable[] available,
                                 int windowSystemRecommendedChoice) {
-    GLCapabilities _desired = (GLCapabilities) desired;
-    GLCapabilities[] _available = (GLCapabilities[]) available;
+    GLCapabilitiesImmutable _desired = (GLCapabilitiesImmutable) desired;
+    GLCapabilitiesImmutable[] _available = (GLCapabilitiesImmutable[]) available;
     int availnum = 0;
 
     for (int i = 0; i < _available.length; i++) {
@@ -132,7 +132,7 @@ public class DefaultGLCapabilitiesChooser implements GLCapabilitiesChooser {
     }
     // Compute score for each
     for (int i = 0; i < scores.length; i++) {
-      GLCapabilities cur = _available[i];
+      GLCapabilitiesImmutable cur = _available[i];
       if (cur == null) {
         continue;
       }
@@ -177,7 +177,7 @@ public class DefaultGLCapabilitiesChooser implements GLCapabilitiesChooser {
       if (score == NO_SCORE) {
         continue;
       }
-      GLCapabilities cur = _available[i];
+      GLCapabilitiesImmutable cur = _available[i];
       if (cur.getHardwareAccelerated()) {
         int absScore = Math.abs(score);
         if (!gotHW ||
@@ -193,7 +193,7 @@ public class DefaultGLCapabilitiesChooser implements GLCapabilitiesChooser {
         if (score == NO_SCORE) {
           continue;
         }
-        GLCapabilities cur = _available[i];
+        GLCapabilitiesImmutable cur = _available[i];
         if (!cur.getHardwareAccelerated()) {
           if (score <= 0) {
             score -= maxAbsoluteHWScore;
diff --git a/src/jogl/classes/javax/media/opengl/GLCapabilities.java b/src/jogl/classes/javax/media/opengl/GLCapabilities.java
index d48b95c79..3d2e2bcc9 100644
--- a/src/jogl/classes/javax/media/opengl/GLCapabilities.java
+++ b/src/jogl/classes/javax/media/opengl/GLCapabilities.java
@@ -53,7 +53,7 @@ import javax.media.nativewindow.Capabilities;
 
     It currently contains the minimal number of routines which allow
     configuration on all supported window systems. */
-public class GLCapabilities extends Capabilities implements Cloneable {
+public class GLCapabilities extends Capabilities implements Cloneable, GLCapabilitiesImmutable {
   private GLProfile glProfile = null;
   private boolean pbuffer = false;
   private boolean doubleBuffered = true;
@@ -84,6 +84,10 @@ public class GLCapabilities extends Capabilities implements Cloneable {
       glProfile = (null!=glp)?glp:GLProfile.getDefault(GLProfile.getDefaultDevice());
   }
 
+  public Object cloneMutable() {
+    return clone();
+  }
+
   public Object clone() {
     try {
       return super.clone();
@@ -92,12 +96,32 @@ public class GLCapabilities extends Capabilities implements Cloneable {
     }
   }
 
+  public int hashCode() {
+    // 31 * x == (x << 5) - x
+    int hash = 31 + this.glProfile.hashCode() ;
+    hash = ((hash << 5) - hash) + ( this.pbuffer ? 1 : 0 );
+    hash = ((hash << 5) - hash) + ( this.stereo ? 1 : 0 );
+    hash = ((hash << 5) - hash) + ( this.hardwareAccelerated ? 1 : 0 );
+    hash = ((hash << 5) - hash) + this.depthBits;
+    hash = ((hash << 5) - hash) + this.stencilBits;
+    hash = ((hash << 5) - hash) + this.accumRedBits;
+    hash = ((hash << 5) - hash) + this.accumGreenBits;
+    hash = ((hash << 5) - hash) + this.accumBlueBits;
+    hash = ((hash << 5) - hash) + this.accumAlphaBits;
+    hash = ((hash << 5) - hash) + ( this.sampleBuffers ? 1 : 0 );
+    hash = ((hash << 5) - hash) + this.numSamples;
+    hash = ((hash << 5) - hash) + ( this.pbufferFloatingPointBuffers ? 1 : 0 );
+    hash = ((hash << 5) - hash) + ( this.pbufferRenderToTexture ? 1 : 0 );
+    hash = ((hash << 5) - hash) + ( this.pbufferRenderToTextureRectangle ? 1 : 0 );
+    return hash;
+  }
+
   public boolean equals(Object obj) {
     if(this == obj)  { return true; }
-    if(!(obj instanceof GLCapabilities)) {
+    if(!(obj instanceof GLCapabilitiesImmutable)) {
         return false;
     }
-    GLCapabilities other = (GLCapabilities)obj;
+    GLCapabilitiesImmutable other = (GLCapabilitiesImmutable)obj;
     boolean res = super.equals(obj) &&
                   other.getGLProfile()==glProfile &&
                   other.isPBuffer()==pbuffer &&
diff --git a/src/jogl/classes/javax/media/opengl/GLCapabilitiesImmutable.java b/src/jogl/classes/javax/media/opengl/GLCapabilitiesImmutable.java
new file mode 100644
index 000000000..7224d65a8
--- /dev/null
+++ b/src/jogl/classes/javax/media/opengl/GLCapabilitiesImmutable.java
@@ -0,0 +1,147 @@
+/**
+ * Copyright 2010 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
+package javax.media.opengl;
+
+import com.jogamp.common.type.WriteCloneable;
+import javax.media.nativewindow.CapabilitiesImmutable;
+
+/**
+ * Specifies an immutable set of OpenGL capabilities.<br>
+ *
+ * @see javax.media.opengl.GLCapabilities
+ * @see javax.media.nativewindow.CapabilitiesImmutable
+ */
+public interface GLCapabilitiesImmutable extends WriteCloneable, CapabilitiesImmutable {
+
+    /**
+     * Returns the number of bits requested for the accumulation
+     * buffer's alpha component. On some systems only the accumulation
+     * buffer depth, which is the sum of the red, green, and blue bits,
+     * is considered.
+     */
+    int getAccumAlphaBits();
+
+    /**
+     * Returns the number of bits requested for the accumulation
+     * buffer's blue component. On some systems only the accumulation
+     * buffer depth, which is the sum of the red, green, and blue bits,
+     * is considered.
+     */
+    int getAccumBlueBits();
+
+    /**
+     * Returns the number of bits requested for the accumulation
+     * buffer's green component. On some systems only the accumulation
+     * buffer depth, which is the sum of the red, green, and blue bits,
+     * is considered.
+     */
+    int getAccumGreenBits();
+
+    /**
+     * Returns the number of bits requested for the accumulation
+     * buffer's red component. On some systems only the accumulation
+     * buffer depth, which is the sum of the red, green, and blue bits,
+     * is considered.
+     */
+    int getAccumRedBits();
+
+    /**
+     * Returns the number of bits requested for the depth buffer.
+     */
+    int getDepthBits();
+
+    /**
+     * Indicates whether double-buffering is enabled.
+     */
+    boolean getDoubleBuffered();
+
+    /**
+     * Returns the GL profile you desire or used by the drawable.
+     */
+    GLProfile getGLProfile();
+
+    /**
+     * Indicates whether hardware acceleration is enabled.
+     */
+    boolean getHardwareAccelerated();
+
+    /**
+     * Returns the number of sample buffers to be allocated if sample
+     * buffers are enabled. Defaults to 2.
+     */
+    int getNumSamples();
+
+    /**
+     * For pbuffers only, returns whether floating-point buffers should
+     * be used if available. Defaults to false.
+     */
+    boolean getPbufferFloatingPointBuffers();
+
+    /**
+     * For pbuffers only, returns whether the render-to-texture
+     * extension should be used if available.  Defaults to false.
+     */
+    boolean getPbufferRenderToTexture();
+
+    /**
+     * For pbuffers only, returns whether the render-to-texture
+     * extension should be used. Defaults to false.
+     */
+    boolean getPbufferRenderToTextureRectangle();
+
+    /**
+     * Returns whether sample buffers for full-scene antialiasing
+     * (FSAA) should be allocated for this drawable. Defaults to
+     * false.
+     */
+    boolean getSampleBuffers();
+
+    /**
+     * Returns the number of bits requested for the stencil buffer.
+     */
+    int getStencilBits();
+
+    /**
+     * Indicates whether stereo is enabled.
+     */
+    boolean getStereo();
+
+    /**
+     * Indicates whether pbuffer is used/requested.
+     */
+    boolean isPBuffer();
+
+    Object cloneMutable();
+
+    boolean equals(Object obj);
+
+    int hashCode();
+
+    String toString();
+}
diff --git a/src/jogl/classes/javax/media/opengl/GLDrawable.java b/src/jogl/classes/javax/media/opengl/GLDrawable.java
index e4861edd2..f4cd77059 100644
--- a/src/jogl/classes/javax/media/opengl/GLDrawable.java
+++ b/src/jogl/classes/javax/media/opengl/GLDrawable.java
@@ -40,7 +40,9 @@
 
 package javax.media.opengl;
 
-import javax.media.nativewindow.*;
+import javax.media.nativewindow.AbstractGraphicsConfiguration;
+import javax.media.nativewindow.NativeSurface;
+
 
 /** An abstraction for an OpenGL rendering target. A GLDrawable's
     primary functionality is to create OpenGL contexts which can be
@@ -139,7 +141,7 @@ public interface GLDrawable {
       automatically and should not be called by the end user. */
   public void swapBuffers() throws GLException;
 
-  /** Fetches the {@link GLCapabilities} corresponding to the chosen
+  /** Fetches the {@link GLCapabilitiesImmutable} corresponding to the chosen
       OpenGL capabilities (pixel format / visual / GLProfile) for this drawable.<br>
       On some platforms, the pixel format is not directly associated
       with the drawable; a best attempt is made to return a reasonable
@@ -149,7 +151,7 @@ public interface GLDrawable {
       they should reflect those as well.
       @return A copy of the queried object.
     */
-  public GLCapabilities getChosenGLCapabilities();
+  public GLCapabilitiesImmutable getChosenGLCapabilities();
 
   /** Fetches the {@link GLProfile} for this drawable.
       Returns the GLProfile object, no copy.
diff --git a/src/jogl/classes/javax/media/opengl/GLDrawableFactory.java b/src/jogl/classes/javax/media/opengl/GLDrawableFactory.java
index ab23e18f8..fd6aa7859 100644
--- a/src/jogl/classes/javax/media/opengl/GLDrawableFactory.java
+++ b/src/jogl/classes/javax/media/opengl/GLDrawableFactory.java
@@ -329,7 +329,7 @@ public abstract class GLDrawableFactory {
    * @throws GLException if any window system-specific errors caused
    *         the creation of the Offscreen to fail.
    */
-  public abstract GLDrawable createOffscreenDrawable(GLCapabilities capabilities,
+  public abstract GLDrawable createOffscreenDrawable(GLCapabilitiesImmutable capabilities,
                                                      GLCapabilitiesChooser chooser,
                                                      int width, int height)
     throws GLException;
@@ -347,7 +347,7 @@ public abstract class GLDrawableFactory {
    * @throws GLException if any window system-specific errors caused
    *         the creation of the GLPbuffer to fail.
    */
-  public abstract GLDrawable createGLPbufferDrawable(GLCapabilities capabilities,
+  public abstract GLDrawable createGLPbufferDrawable(GLCapabilitiesImmutable capabilities,
                                                      GLCapabilitiesChooser chooser,
                                                      int initialWidth,
                                                      int initialHeight)
@@ -362,7 +362,7 @@ public abstract class GLDrawableFactory {
    * @throws GLException if any window system-specific errors caused
    *         the creation of the GLPbuffer to fail.
    */
-  public abstract GLPbuffer createGLPbuffer(GLCapabilities capabilities,
+  public abstract GLPbuffer createGLPbuffer(GLCapabilitiesImmutable capabilities,
                                             GLCapabilitiesChooser chooser,
                                             int initialWidth,
                                             int initialHeight,
diff --git a/src/jogl/classes/javax/media/opengl/awt/GLCanvas.java b/src/jogl/classes/javax/media/opengl/awt/GLCanvas.java
index 292bfba7c..dba041f8d 100644
--- a/src/jogl/classes/javax/media/opengl/awt/GLCanvas.java
+++ b/src/jogl/classes/javax/media/opengl/awt/GLCanvas.java
@@ -41,7 +41,6 @@
 package javax.media.opengl.awt;
 
 import com.jogamp.common.GlueGenVersion;
-import com.jogamp.common.util.VersionUtil;
 import com.jogamp.nativewindow.NativeWindowVersion;
 import javax.media.opengl.*;
 import javax.media.nativewindow.*;
@@ -95,7 +94,7 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
   private boolean sendReshape = false;
   
   // copy of the cstr args ..
-  private GLCapabilities capabilities;
+  private GLCapabilitiesImmutable capabilities;
   private GLCapabilitiesChooser chooser;
   private GLContext shareWith;
   private GraphicsDevice device;
@@ -110,8 +109,8 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
   /** Creates a new GLCanvas component with the requested set of
       OpenGL capabilities, using the default OpenGL capabilities
       selection mechanism, on the default screen device. */
-  public GLCanvas(GLCapabilities capabilities) {
-    this(capabilities, null, null, null);
+  public GLCanvas(GLCapabilitiesImmutable capsReqUser) {
+    this(capsReqUser, null, null, null);
   }
 
   /** Creates a new GLCanvas component. The passed GLCapabilities
@@ -129,7 +128,7 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
       which to create the GLCanvas; the GLDrawableFactory uses the
       default screen device of the local GraphicsEnvironment if null
       is passed for this argument. */
-  public GLCanvas(GLCapabilities capabilities,
+  public GLCanvas(GLCapabilitiesImmutable capsReqUser,
                   GLCapabilitiesChooser chooser,
                   GLContext shareWith,
                   GraphicsDevice device) {
@@ -141,12 +140,14 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
      */
     super();
 
-    if(null==capabilities) {
+    if(null==capsReqUser) {
         capabilities = new GLCapabilities(defaultGLProfile);
+    } else {
+        // don't allow the user to change data
+        capabilities = (GLCapabilitiesImmutable) capsReqUser.cloneMutable();
     }
     glProfile = capabilities.getGLProfile();
 
-    this.capabilities = capabilities;
     this.chooser = chooser;
     this.shareWith=shareWith;
     this.device = device;
@@ -231,7 +232,9 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
          * block, both devices should have the same visual list, and the
          * same configuration should be selected here.
          */
-        AWTGraphicsConfiguration config = chooseGraphicsConfiguration((GLCapabilities)awtConfig.getRequestedCapabilities(), chooser, gc.getDevice());
+        AWTGraphicsConfiguration config = chooseGraphicsConfiguration( (GLCapabilitiesImmutable)awtConfig.getChosenCapabilities(),
+                                                                       (GLCapabilitiesImmutable)awtConfig.getRequestedCapabilities(),
+                                                                       chooser, gc.getDevice());
         final GraphicsConfiguration compatible = (null!=config)?config.getGraphicsConfiguration():null;
         boolean equalCaps = config.getChosenCapabilities().equals(awtConfig.getChosenCapabilities());
         if(DEBUG) {
@@ -429,7 +432,7 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
          */
         NativeWindowFactory.getDefaultToolkitLock().lock();
         try {
-            awtConfig = chooseGraphicsConfiguration(capabilities, chooser, device);
+            awtConfig = chooseGraphicsConfiguration(capabilities, capabilities, chooser, device);
             if(DEBUG) {
                 System.err.println(Thread.currentThread().getName()+" - Created Config: "+awtConfig);
             }
@@ -578,20 +581,20 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
     return glProfile;
   }
 
-  public GLCapabilities getChosenGLCapabilities() {
+  public GLCapabilitiesImmutable getChosenGLCapabilities() {
     if (awtConfig == null) {
         throw new GLException("No AWTGraphicsConfiguration: "+this);
     }
 
-    return (GLCapabilities)awtConfig.getChosenCapabilities();
+    return (GLCapabilitiesImmutable)awtConfig.getChosenCapabilities();
   }
 
-  public GLCapabilities getRequestedGLCapabilities() {
+  public GLCapabilitiesImmutable getRequestedGLCapabilities() {
     if (awtConfig == null) {
         throw new GLException("No AWTGraphicsConfiguration: "+this);
     }
 
-    return (GLCapabilities)awtConfig.getRequestedCapabilities();
+    return (GLCapabilitiesImmutable)awtConfig.getRequestedCapabilities();
   }
 
   public NativeSurface getNativeSurface() {
@@ -771,7 +774,8 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
     }
   }
 
-  private static AWTGraphicsConfiguration chooseGraphicsConfiguration(GLCapabilities capabilities,
+  private static AWTGraphicsConfiguration chooseGraphicsConfiguration(GLCapabilitiesImmutable capsChosen,
+                                                                      GLCapabilitiesImmutable capsRequested,
                                                                       GLCapabilitiesChooser chooser,
                                                                       GraphicsDevice device) {
     // Make GLCanvas behave better in NetBeans GUI builder
@@ -781,9 +785,9 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
 
     AbstractGraphicsScreen aScreen = AWTGraphicsScreen.createScreenDevice(device, AbstractGraphicsDevice.DEFAULT_UNIT);
     AWTGraphicsConfiguration config = (AWTGraphicsConfiguration)
-      GraphicsConfigurationFactory.getFactory(AWTGraphicsDevice.class).chooseGraphicsConfiguration(capabilities,
-                                                                                                   chooser,
-                                                                                                   aScreen);
+      GraphicsConfigurationFactory.getFactory(AWTGraphicsDevice.class).chooseGraphicsConfiguration(capsChosen,
+                                                                                                   capsRequested,
+                                                                                                   chooser, aScreen);
     if (config == null) {
       throw new GLException("Error: Couldn't fetch AWTGraphicsConfiguration");
     }
@@ -799,7 +803,7 @@ public class GLCanvas extends Canvas implements AWTGLAutoDrawable {
     System.err.println(NativeWindowVersion.getInstance());
     System.err.print(JoglVersion.getInstance());
 
-    GLCapabilities caps = new GLCapabilities( GLProfile.getDefault(GLProfile.getDefaultDesktopDevice()) );
+    GLCapabilitiesImmutable caps = new GLCapabilities( GLProfile.getDefault(GLProfile.getDefaultDesktopDevice()) );
     Frame frame = new Frame("JOGL AWT Test");
 
     GLCanvas glCanvas = new GLCanvas(caps);
diff --git a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
index 955e51e69..0f724d558 100644
--- a/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
+++ b/src/jogl/classes/javax/media/opengl/awt/GLJPanel.java
@@ -91,7 +91,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
   private volatile boolean isInitialized;
 
   // Data used for either pbuffers or pixmap-based offscreen surfaces
-  private GLCapabilities        offscreenCaps;
+  private GLCapabilitiesImmutable offscreenCaps;
   private GLProfile             glProfile;
   private GLDrawableFactoryImpl factory;
   private GLCapabilitiesChooser chooser;
@@ -158,8 +158,8 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
   /** Creates a new GLJPanel component with the requested set of
       OpenGL capabilities, using the default OpenGL capabilities
       selection mechanism. */
-  public GLJPanel(GLCapabilities capabilities) {
-    this(capabilities, null, null);
+  public GLJPanel(GLCapabilitiesImmutable userCapsRequest) {
+    this(userCapsRequest, null, null);
   }
 
   /** Creates a new GLJPanel component. The passed GLCapabilities
@@ -176,17 +176,21 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
       Note: Sharing cannot be enabled using J2D OpenGL FBO sharing,
       since J2D GL Context must be shared and we can only share one context.
   */
-  public GLJPanel(GLCapabilities capabilities, GLCapabilitiesChooser chooser, GLContext shareWith) {
+  public GLJPanel(GLCapabilitiesImmutable userCapsRequest, GLCapabilitiesChooser chooser, GLContext shareWith) {
     super();
 
     // Works around problems on many vendors' cards; we don't need a
     // back buffer for the offscreen surface anyway
-    if (capabilities != null) {
-        offscreenCaps = (GLCapabilities) capabilities.clone();
-    } else {
-        offscreenCaps = new GLCapabilities(null);
+    {
+        GLCapabilities caps;
+        if (userCapsRequest != null) {
+            caps = (GLCapabilities) userCapsRequest.cloneMutable();
+        } else {
+            caps = new GLCapabilities(null);
+        }
+        caps.setDoubleBuffered(false);
+        offscreenCaps = caps;
     }
-    offscreenCaps.setDoubleBuffered(false);
     this.glProfile = offscreenCaps.getGLProfile();
     this.factory = GLDrawableFactoryImpl.getFactoryImpl(glProfile);
     this.chooser = ((chooser != null) ? chooser : new DefaultGLCapabilitiesChooser());
@@ -485,7 +489,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
     return oglPipelineEnabled;
   }
 
-  public GLCapabilities getChosenGLCapabilities() {
+  public GLCapabilitiesImmutable getChosenGLCapabilities() {
     return backend.getChosenGLCapabilities();
   }
 
@@ -748,7 +752,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
     public GLDrawable getDrawable();
 
     // Called to fetch the "real" GLCapabilities for the backend
-    public GLCapabilities getChosenGLCapabilities();
+    public GLCapabilitiesImmutable getChosenGLCapabilities();
 
     // Called to fetch the "real" GLProfile for the backend
     public GLProfile getGLProfile();
@@ -992,7 +996,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
         return offscreenDrawable;
     }
 
-    public GLCapabilities getChosenGLCapabilities() {
+    public GLCapabilitiesImmutable getChosenGLCapabilities() {
       if (offscreenDrawable == null) {
         return null;
       }
@@ -1090,7 +1094,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
         return pbuffer;
     }
 
-    public GLCapabilities getChosenGLCapabilities() {
+    public GLCapabilitiesImmutable getChosenGLCapabilities() {
       if (pbuffer == null) {
         return null;
       }
@@ -1268,7 +1272,7 @@ public class GLJPanel extends JPanel implements AWTGLAutoDrawable {
         return joglDrawable;
     }
 
-    public GLCapabilities getChosenGLCapabilities() {
+    public GLCapabilitiesImmutable getChosenGLCapabilities() {
       // FIXME: should do better than this; is it possible to using only platform-independent code?
       return new GLCapabilities(null);
     }
diff --git a/src/junit/com/jogamp/test/junit/jogl/demos/gl2/gears/newt/TestGearsNewtAWTWrapper.java b/src/junit/com/jogamp/test/junit/jogl/demos/gl2/gears/newt/TestGearsNewtAWTWrapper.java
index ef4b657fc..d0b8cc7de 100644
--- a/src/junit/com/jogamp/test/junit/jogl/demos/gl2/gears/newt/TestGearsNewtAWTWrapper.java
+++ b/src/junit/com/jogamp/test/junit/jogl/demos/gl2/gears/newt/TestGearsNewtAWTWrapper.java
@@ -63,7 +63,7 @@ public class TestGearsNewtAWTWrapper extends UITestCase {
     public static void releaseClass() {
     }
 
-    protected void runTestGL(GLCapabilities caps) throws InterruptedException {
+    protected void runTestGL(GLCapabilitiesImmutable caps) throws InterruptedException {
         Display nDisplay = NewtFactory.createDisplay(NativeWindowFactory.TYPE_AWT, null, false); // local display
         Screen nScreen  = NewtFactory.createScreen(nDisplay, 0); // screen 0
         Window nWindow = NewtFactory.createWindow(nScreen, caps);
@@ -94,7 +94,7 @@ public class TestGearsNewtAWTWrapper extends UITestCase {
 
     @Test
     public void test01() throws InterruptedException {
-        GLCapabilities caps = new GLCapabilities(GLProfile.getDefault());
+        GLCapabilitiesImmutable caps = new GLCapabilities(GLProfile.getDefault());
         runTestGL(caps);
     }
 
diff --git a/src/junit/com/jogamp/test/junit/jogl/offscreen/WindowUtilNEWT.java b/src/junit/com/jogamp/test/junit/jogl/offscreen/WindowUtilNEWT.java
index 6deacf726..cfe956c61 100644
--- a/src/junit/com/jogamp/test/junit/jogl/offscreen/WindowUtilNEWT.java
+++ b/src/junit/com/jogamp/test/junit/jogl/offscreen/WindowUtilNEWT.java
@@ -41,7 +41,7 @@ import com.jogamp.newt.opengl.*;
 public class WindowUtilNEWT {
 
     public static GLCapabilities fixCaps(GLCapabilities caps, boolean onscreen, boolean pbuffer, boolean undecorated) {
-        GLCapabilities caps2 = (GLCapabilities) caps.clone();
+        GLCapabilities caps2 = (GLCapabilities) caps.cloneMutable();
         caps2.setOnscreen(onscreen);
         caps2.setPBuffer(!onscreen && pbuffer);
         caps2.setDoubleBuffered(!onscreen);
diff --git a/src/junit/com/jogamp/test/junit/newt/TestGLWindows00NEWT.java b/src/junit/com/jogamp/test/junit/newt/TestGLWindows00NEWT.java
index d28dd2c11..2769dc550 100644
--- a/src/junit/com/jogamp/test/junit/newt/TestGLWindows00NEWT.java
+++ b/src/junit/com/jogamp/test/junit/newt/TestGLWindows00NEWT.java
@@ -58,7 +58,7 @@ public class TestGLWindows00NEWT extends UITestCase {
         glp = GLProfile.getDefault();
     }
 
-    static GLWindow createWindow(Screen screen, GLCapabilities caps)
+    static GLWindow createWindow(Screen screen, GLCapabilitiesImmutable caps)
         throws InterruptedException
     {
         Assert.assertNotNull(caps);
diff --git a/src/junit/com/jogamp/test/junit/newt/TestGLWindows01NEWT.java b/src/junit/com/jogamp/test/junit/newt/TestGLWindows01NEWT.java
index 934d75f7c..e2c65adb8 100644
--- a/src/junit/com/jogamp/test/junit/newt/TestGLWindows01NEWT.java
+++ b/src/junit/com/jogamp/test/junit/newt/TestGLWindows01NEWT.java
@@ -57,7 +57,7 @@ public class TestGLWindows01NEWT extends UITestCase {
         glp = GLProfile.getDefault();
     }
 
-    static GLWindow createWindow(Screen screen, GLCapabilities caps, 
+    static GLWindow createWindow(Screen screen, GLCapabilities caps,
                                  int width, int height, boolean onscreen, boolean undecorated,
                                  boolean addGLEventListenerAfterVisible) 
         throws InterruptedException
@@ -102,12 +102,12 @@ public class TestGLWindows01NEWT extends UITestCase {
         // Create native OpenGL resources .. XGL/WGL/CGL .. 
         // equivalent to GLAutoDrawable methods: setVisible(true)
         // 
-        caps = glWindow.getChosenGLCapabilities();
-        Assert.assertNotNull(caps);
-        Assert.assertTrue(caps.getGreenBits()>5);
-        Assert.assertTrue(caps.getBlueBits()>5);
-        Assert.assertTrue(caps.getRedBits()>5);
-        Assert.assertEquals(caps.isOnscreen(),onscreen);
+        GLCapabilitiesImmutable caps2 = glWindow.getChosenGLCapabilities();
+        Assert.assertNotNull(caps2);
+        Assert.assertTrue(caps2.getGreenBits()>=5);
+        Assert.assertTrue(caps2.getBlueBits()>=5);
+        Assert.assertTrue(caps2.getRedBits()>=5);
+        Assert.assertEquals(caps2.isOnscreen(),onscreen);
 
         if(addGLEventListenerAfterVisible) {
             glWindow.addGLEventListener(demo);
diff --git a/src/junit/com/jogamp/test/junit/newt/TestGLWindows02NEWTAnimated.java b/src/junit/com/jogamp/test/junit/newt/TestGLWindows02NEWTAnimated.java
index 78b9773a8..e79d57a4f 100644
--- a/src/junit/com/jogamp/test/junit/newt/TestGLWindows02NEWTAnimated.java
+++ b/src/junit/com/jogamp/test/junit/newt/TestGLWindows02NEWTAnimated.java
@@ -104,12 +104,12 @@ public class TestGLWindows02NEWTAnimated extends UITestCase {
         // Create native OpenGL resources .. XGL/WGL/CGL .. 
         // equivalent to GLAutoDrawable methods: setVisible(true)
         // 
-        caps = glWindow.getChosenGLCapabilities();
-        Assert.assertNotNull(caps);
-        Assert.assertTrue(caps.getGreenBits()>5);
-        Assert.assertTrue(caps.getBlueBits()>5);
-        Assert.assertTrue(caps.getRedBits()>5);
-        Assert.assertEquals(caps.isOnscreen(),onscreen);
+        GLCapabilitiesImmutable caps2 = glWindow.getChosenGLCapabilities();
+        Assert.assertNotNull(caps2);
+        Assert.assertTrue(caps2.getGreenBits()>=5);
+        Assert.assertTrue(caps2.getBlueBits()>=5);
+        Assert.assertTrue(caps2.getRedBits()>=5);
+        Assert.assertEquals(caps2.isOnscreen(),onscreen);
 
         return glWindow;
     }
diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/impl/GraphicsConfigurationFactoryImpl.java b/src/nativewindow/classes/com/jogamp/nativewindow/impl/GraphicsConfigurationFactoryImpl.java
index 96f6ab2ba..c53f4c88b 100644
--- a/src/nativewindow/classes/com/jogamp/nativewindow/impl/GraphicsConfigurationFactoryImpl.java
+++ b/src/nativewindow/classes/com/jogamp/nativewindow/impl/GraphicsConfigurationFactoryImpl.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2009 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -36,7 +37,7 @@ import javax.media.nativewindow.*;
 
 public class GraphicsConfigurationFactoryImpl extends GraphicsConfigurationFactory {
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-            Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen screen) {
-        return new DefaultGraphicsConfiguration(screen, capabilities, capabilities);
+            CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested, CapabilitiesChooser chooser, AbstractGraphicsScreen screen) {
+        return new DefaultGraphicsConfiguration(screen, capsChosen, capsRequested);
     }
 }
diff --git a/src/nativewindow/classes/com/jogamp/nativewindow/impl/x11/X11GraphicsConfigurationFactory.java b/src/nativewindow/classes/com/jogamp/nativewindow/impl/x11/X11GraphicsConfigurationFactory.java
index ff07fab44..fec7ca29d 100644
--- a/src/nativewindow/classes/com/jogamp/nativewindow/impl/x11/X11GraphicsConfigurationFactory.java
+++ b/src/nativewindow/classes/com/jogamp/nativewindow/impl/x11/X11GraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -34,18 +35,16 @@ package com.jogamp.nativewindow.impl.x11;
 
 import javax.media.nativewindow.*;
 import javax.media.nativewindow.x11.*;
-import com.jogamp.nativewindow.impl.x11.XVisualInfo;
-import com.jogamp.nativewindow.impl.x11.X11Lib;
 
 public class X11GraphicsConfigurationFactory extends GraphicsConfigurationFactory {
     protected AbstractGraphicsConfiguration chooseGraphicsConfigurationImpl(
-        Capabilities capabilities, CapabilitiesChooser chooser, AbstractGraphicsScreen screen)
+        CapabilitiesImmutable  capsChosen, CapabilitiesImmutable capsRequested, CapabilitiesChooser chooser, AbstractGraphicsScreen screen)
         throws IllegalArgumentException, NativeWindowException {
 
         if(!(screen instanceof X11GraphicsScreen)) {
             throw new NativeWindowException("Only valid X11GraphicsScreen are allowed");
         }
-        return new X11GraphicsConfiguration((X11GraphicsScreen)screen, capabilities, capabilities, getXVisualInfo(screen, capabilities));
+        return new X11GraphicsConfiguration((X11GraphicsScreen)screen,  capsChosen, capsRequested, getXVisualInfo(screen, capsChosen));
     }
 
     public static XVisualInfo getXVisualInfo(AbstractGraphicsScreen screen, long visualID)
diff --git a/src/nativewindow/classes/javax/media/nativewindow/Capabilities.java b/src/nativewindow/classes/javax/media/nativewindow/Capabilities.java
index ff6e077ee..e844c4f3e 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/Capabilities.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/Capabilities.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -43,7 +44,6 @@ package javax.media.nativewindow;
     must support, such as color depth per channel. It currently
     contains the minimal number of routines which allow configuration
     on all supported window systems. */
-
 public class Capabilities implements CapabilitiesImmutable, Cloneable {
   private int     redBits        = 8;
   private int     greenBits      = 8;
@@ -65,8 +65,8 @@ public class Capabilities implements CapabilitiesImmutable, Cloneable {
     */
   public Capabilities() {}
 
-    public Capabilities cloneCapabilites() {
-      return (Capabilities) clone();
+  public Object cloneMutable() {
+    return clone();
   }
   
   public Object clone() {
@@ -77,12 +77,27 @@ public class Capabilities implements CapabilitiesImmutable, Cloneable {
     }
   }
 
+  public int hashCode() {
+    // 31 * x == (x << 5) - x
+    int hash = 31 + this.redBits;
+    hash = ((hash << 5) - hash) + this.greenBits;
+    hash = ((hash << 5) - hash) + this.blueBits;
+    hash = ((hash << 5) - hash) + this.alphaBits;
+    hash = ((hash << 5) - hash) + ( this.backgroundOpaque ? 1 : 0 );
+    hash = ((hash << 5) - hash) + this.transparentValueRed;
+    hash = ((hash << 5) - hash) + this.transparentValueGreen;
+    hash = ((hash << 5) - hash) + this.transparentValueBlue;
+    hash = ((hash << 5) - hash) + this.transparentValueAlpha;
+    hash = ((hash << 5) - hash) + ( this.onscreen ? 1 : 0 );
+    return hash;
+  }
+
   public boolean equals(Object obj) {
     if(this == obj)  { return true; }
-    if(!(obj instanceof Capabilities)) {
+    if(!(obj instanceof CapabilitiesImmutable)) {
         return false;
     }
-    Capabilities other = (Capabilities)obj;
+    CapabilitiesImmutable other = (CapabilitiesImmutable)obj;
     boolean res = other.getRedBits()==redBits &&
                   other.getGreenBits()==greenBits &&
                   other.getBlueBits()==blueBits &&
diff --git a/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesChooser.java b/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesChooser.java
index d61ebd4ef..94b0f68af 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesChooser.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesChooser.java
@@ -62,7 +62,7 @@ public interface CapabilitiesChooser {
       invoked by users directly, unless it is desired to delegate the
       choice to some other CapabilitiesChooser object.
   */
-  public int chooseCapabilities(Capabilities desired,
-                                Capabilities[] available,
+  public int chooseCapabilities(CapabilitiesImmutable desired,
+                                CapabilitiesImmutable[] available,
                                 int windowSystemRecommendedChoice);
 }
diff --git a/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesImmutable.java b/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesImmutable.java
index 9369221cb..72828b9f0 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesImmutable.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/CapabilitiesImmutable.java
@@ -1,12 +1,42 @@
+/**
+ * Copyright 2010 JogAmp Community. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification, are
+ * permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice, this list of
+ *       conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright notice, this list
+ *       of conditions and the following disclaimer in the documentation and/or other materials
+ *       provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * The views and conclusions contained in the software and documentation are those of the
+ * authors and should not be interpreted as representing official policies, either expressed
+ * or implied, of JogAmp Community.
+ */
+
 package javax.media.nativewindow;
 
+import com.jogamp.common.type.WriteCloneable;
+
 /**
  * Specifies an immutable set of capabilities that a window's rendering context
  * must support, such as color depth per channel.
  * 
  * @see javax.media.nativewindow.Capabilities
  */
-public interface CapabilitiesImmutable extends Cloneable {
+public interface CapabilitiesImmutable extends WriteCloneable {
 
     /**
      * Returns the number of bits requested for the color buffer's red
@@ -71,11 +101,14 @@ public interface CapabilitiesImmutable extends Cloneable {
      */
     int getTransparentAlphaValue();
 
-    /**
-     * Get a mutable clone of this instance.
-     * 
-     * @see java.lang.Object#clone()
-     */
-    Capabilities cloneCapabilites();
+    Object cloneMutable();
+    
+    /** Equality over the immutable attributes of both objects */
+    boolean equals(Object obj);
+
+    /** hash code over the immutable attributes of both objects */
+    int hashCode();
 
+    /** Returns a textual representation of this object. */
+    String toString();
 }
diff --git a/src/nativewindow/classes/javax/media/nativewindow/DefaultCapabilitiesChooser.java b/src/nativewindow/classes/javax/media/nativewindow/DefaultCapabilitiesChooser.java
index cead0a4a8..856c29420 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/DefaultCapabilitiesChooser.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/DefaultCapabilitiesChooser.java
@@ -63,8 +63,8 @@ package javax.media.nativewindow;
 public class DefaultCapabilitiesChooser implements CapabilitiesChooser {
   private static final boolean DEBUG = false; // FIXME: Debug.debug("DefaultCapabilitiesChooser");
 
-  public int chooseCapabilities(Capabilities desired,
-                                Capabilities[] available,
+  public int chooseCapabilities(CapabilitiesImmutable desired,
+                                CapabilitiesImmutable[] available,
                                 int windowSystemRecommendedChoice) {
     if (DEBUG) {
       System.err.println("Desired: " + desired);
@@ -93,7 +93,7 @@ public class DefaultCapabilitiesChooser implements CapabilitiesChooser {
     }
     // Compute score for each
     for (int i = 0; i < scores.length; i++) {
-      Capabilities cur = available[i];
+      CapabilitiesImmutable cur = available[i];
       if (cur == null) {
         continue;
       }
diff --git a/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsConfiguration.java b/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsConfiguration.java
index 3d06388c2..47110add9 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsConfiguration.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/DefaultGraphicsConfiguration.java
@@ -41,9 +41,8 @@ public class DefaultGraphicsConfiguration implements Cloneable, AbstractGraphics
                                         CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested) {
         this.screen = screen;
 
-        // Create "immutable" copies of capabilities.
-        this.capabilitiesChosen = capsChosen.cloneCapabilites();
-        this.capabilitiesRequested = capsRequested.cloneCapabilites();
+        this.capabilitiesChosen = capsChosen;
+        this.capabilitiesRequested = capsRequested;
     }
 
     public Object clone() {
@@ -76,13 +75,12 @@ public class DefaultGraphicsConfiguration implements Cloneable, AbstractGraphics
      * The use case for setting the Capabilities at a later time is
      * a change of the graphics device in a multi-screen environment.<br>
      *
-     * A copy of the passed object is being used.
+     * The objects reference is being used.
      *
      * @see javax.media.nativewindow.GraphicsConfigurationFactory#chooseGraphicsConfiguration(Capabilities, CapabilitiesChooser, AbstractGraphicsScreen)
      */
     protected void setChosenCapabilities(CapabilitiesImmutable capsChosen) {
-        // Create "immutable" copy of capabilities.
-        capabilitiesChosen = (CapabilitiesImmutable) capsChosen.cloneCapabilites();
+        capabilitiesChosen = capsChosen;
     }
 
     /**
diff --git a/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java b/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
index 1d3a7445f..c061f597f 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/GraphicsConfigurationFactory.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008-2009 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -32,7 +33,6 @@
 
 package javax.media.nativewindow;
 
-import java.lang.reflect.*;
 import java.util.*;
 
 import com.jogamp.common.util.*;
@@ -187,6 +187,12 @@ public abstract class GraphicsConfigurationFactory {
      * javax.media.nativewindow.x11.X11GraphicsConfiguration
      * X11GraphicsConfiguration} objects.</P>
      *
+     * @param capsChosen     the intermediate chosen capabilities to be refined by this implementation, may be equal to capsRequested
+     * @param capsRequested  the original requested capabilities
+     * @param chooser        the choosing implementation
+     * @param screen         the referring Screen
+     * @return               the complete GraphicsConfiguration
+     *
      * @throws IllegalArgumentException if the data type of the passed
      *         AbstractGraphicsDevice is not supported by this
      *         NativeWindowFactory.
@@ -197,10 +203,16 @@ public abstract class GraphicsConfigurationFactory {
      * @see javax.media.nativewindow.DefaultGraphicsConfiguration#setChosenCapabilities(Capabilities caps)
      */
     public final AbstractGraphicsConfiguration
-        chooseGraphicsConfiguration(Capabilities capabilities,
+        chooseGraphicsConfiguration(CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
                                     CapabilitiesChooser chooser,
                                     AbstractGraphicsScreen screen)
         throws IllegalArgumentException, NativeWindowException {
+        if(null==capsChosen) {
+            throw new NativeWindowException("Chosen Capabilities are null");
+        }
+        if(null==capsRequested) {
+            throw new NativeWindowException("Requested Capabilities are null");
+        }
         if(null==screen) {
             throw new NativeWindowException("Screen is null");
         }
@@ -210,15 +222,14 @@ public abstract class GraphicsConfigurationFactory {
         }
         device.lock();
         try {
-            return chooseGraphicsConfigurationImpl(capabilities, chooser, screen);            
+            return chooseGraphicsConfigurationImpl(capsChosen, capsRequested, chooser, screen);
         } finally {
             device.unlock();
         }
     }
 
     protected abstract AbstractGraphicsConfiguration
-        chooseGraphicsConfigurationImpl(Capabilities capabilities,
-                                    CapabilitiesChooser chooser,
-                                    AbstractGraphicsScreen screen)
+        chooseGraphicsConfigurationImpl(CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+                                        CapabilitiesChooser chooser, AbstractGraphicsScreen screen)
         throws IllegalArgumentException, NativeWindowException;
 }
diff --git a/src/nativewindow/classes/javax/media/nativewindow/awt/AWTGraphicsConfiguration.java b/src/nativewindow/classes/javax/media/nativewindow/awt/AWTGraphicsConfiguration.java
index bce9b248d..41051ab46 100644
--- a/src/nativewindow/classes/javax/media/nativewindow/awt/AWTGraphicsConfiguration.java
+++ b/src/nativewindow/classes/javax/media/nativewindow/awt/AWTGraphicsConfiguration.java
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2005 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright (c) 2010 JogAmp Community. All rights reserved.
  * 
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -63,7 +64,8 @@ public class AWTGraphicsConfiguration extends DefaultGraphicsConfiguration imple
     this.encapsulated=encapsulated;
   }
 
-  public AWTGraphicsConfiguration(AWTGraphicsScreen screen, CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested, GraphicsConfiguration config) {
+  public AWTGraphicsConfiguration(AWTGraphicsScreen screen, CapabilitiesImmutable capsChosen, CapabilitiesImmutable capsRequested,
+                                  GraphicsConfiguration config) {
     super(screen, capsChosen, capsRequested);
     this.config = config;
     this.encapsulated=null;
@@ -97,7 +99,7 @@ public class AWTGraphicsConfiguration extends DefaultGraphicsConfiguration imple
 
       if(null==capsChosen) {
           GraphicsConfiguration gc = awtGraphicsDevice.getDefaultConfiguration();
-          capsChosen = setupCapabilitiesRGBABits(capsRequested.cloneCapabilites(), gc);
+          capsChosen = setupCapabilitiesRGBABits(capsChosen, gc);
       }
       return new AWTGraphicsConfiguration(awtScreen, capsChosen, capsRequested, awtGfxConfig);
   }
@@ -121,7 +123,9 @@ public class AWTGraphicsConfiguration extends DefaultGraphicsConfiguration imple
    * @param gc the GraphicsConfiguration from which to derive the RGBA bit depths
    * @return the passed Capabilities
    */
-  public static Capabilities setupCapabilitiesRGBABits(Capabilities capabilities, GraphicsConfiguration gc) {
+  public static CapabilitiesImmutable setupCapabilitiesRGBABits(CapabilitiesImmutable capabilitiesIn, GraphicsConfiguration gc) {
+    Capabilities capabilities = (Capabilities) capabilitiesIn.cloneMutable();
+    
     int cmTransparency = capabilities.isBackgroundOpaque()?Transparency.OPAQUE:Transparency.TRANSLUCENT;
     ColorModel cm = gc.getColorModel(cmTransparency);
     if(null==cm && !capabilities.isBackgroundOpaque()) {
diff --git a/src/newt/classes/com/jogamp/newt/NewtFactory.java b/src/newt/classes/com/jogamp/newt/NewtFactory.java
index 892a2426e..3b836787e 100644
--- a/src/newt/classes/com/jogamp/newt/NewtFactory.java
+++ b/src/newt/classes/com/jogamp/newt/NewtFactory.java
@@ -112,14 +112,14 @@ public class NewtFactory {
      * The Display/Screen is created and owned, ie destructed atomatically.<br>
      * A new Display is only created if no preexisting one could be found via {@link Display#getLastDisplayOf(java.lang.String, java.lang.String, int)}.
      */
-    public static Window createWindow(Capabilities caps) {
+    public static Window createWindow(CapabilitiesImmutable caps) {
         return createWindowImpl(NativeWindowFactory.getNativeWindowType(true), caps);
     }
 
     /**
      * Create a top level Window entity, incl native creation
      */
-    public static Window createWindow(Screen screen, Capabilities caps) {
+    public static Window createWindow(Screen screen, CapabilitiesImmutable caps) {
         return createWindowImpl(screen, caps);
     }
 
@@ -140,7 +140,7 @@ public class NewtFactory {
      *
      * @param parentWindowObject either a NativeWindow instance
      */
-    public static Window createWindow(NativeWindow nParentWindow, Capabilities caps) {
+    public static Window createWindow(NativeWindow nParentWindow, CapabilitiesImmutable caps) {
         final String type = NativeWindowFactory.getNativeWindowType(true);
 
         Screen screen  = null;
@@ -173,19 +173,19 @@ public class NewtFactory {
         return win;
     }
 
-    protected static Window createWindowImpl(NativeWindow parentNativeWindow, Screen screen, Capabilities caps) {
+    protected static Window createWindowImpl(NativeWindow parentNativeWindow, Screen screen, CapabilitiesImmutable caps) {
         return WindowImpl.create(parentNativeWindow, 0, screen, caps);
     }
 
-    protected static Window createWindowImpl(long parentWindowHandle, Screen screen, Capabilities caps) {
+    protected static Window createWindowImpl(long parentWindowHandle, Screen screen, CapabilitiesImmutable caps) {
         return WindowImpl.create(null, parentWindowHandle, screen, caps);
     }
 
-    protected static Window createWindowImpl(Screen screen, Capabilities caps) {
+    protected static Window createWindowImpl(Screen screen, CapabilitiesImmutable caps) {
         return WindowImpl.create(null, 0, screen, caps);
     }
 
-    protected static Window createWindowImpl(String type, Capabilities caps) {
+    protected static Window createWindowImpl(String type, CapabilitiesImmutable caps) {
         Display display = NewtFactory.createDisplay(type, null, true); // local display
         Screen screen  = NewtFactory.createScreen(display, 0); // screen 0
         return WindowImpl.create(null, 0, screen, caps);
@@ -197,7 +197,7 @@ public class NewtFactory {
      * @param parentWindowObject the native parent window handle
      * @param undecorated only impacts if the window is in top-level state, while attached to a parent window it's rendered undecorated always
      */
-    public static Window createWindow(long parentWindowHandle, Screen screen, Capabilities caps) {
+    public static Window createWindow(long parentWindowHandle, Screen screen, CapabilitiesImmutable caps) {
         return createWindowImpl(parentWindowHandle, screen, caps);
     }
 
@@ -208,7 +208,7 @@ public class NewtFactory {
      *
      * @param undecorated only impacts if the window is in top-level state, while attached to a parent window it's rendered undecorated always
      */
-    public static Window createWindow(Object[] cstrArguments, Screen screen, Capabilities caps) {
+    public static Window createWindow(Object[] cstrArguments, Screen screen, CapabilitiesImmutable caps) {
         return WindowImpl.create(cstrArguments, screen, caps);
     }
 
@@ -219,7 +219,7 @@ public class NewtFactory {
       return DisplayImpl.create(type, null, handle, false);
     }
 
-    private static final boolean instanceOf(Object obj, String clazzName) {
+    private static boolean instanceOf(Object obj, String clazzName) {
         Class clazz = obj.getClass();
         do {
             if(clazz.getName().equals(clazzName)) {
diff --git a/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java b/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
index 29e8c91b4..a0ab5f9f6 100644
--- a/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
+++ b/src/newt/classes/com/jogamp/newt/awt/NewtCanvasAWT.java
@@ -168,8 +168,7 @@ public class NewtCanvasAWT extends java.awt.Canvas {
 
       newtChild.setFocusAction(null); // no AWT focus traversal ..
       if(add) {
-          nativeWindow = NewtFactoryAWT.getNativeWindow(this,
-                  newtChild.getRequestedCapabilities().cloneCapabilites());
+          nativeWindow = NewtFactoryAWT.getNativeWindow(this, newtChild.getRequestedCapabilities());
           if(null!=nativeWindow) {
               if(DEBUG) {
                 System.err.println("NewtCanvasAWT.reparentWindow: "+newtChild);
diff --git a/src/newt/classes/com/jogamp/newt/awt/NewtFactoryAWT.java b/src/newt/classes/com/jogamp/newt/awt/NewtFactoryAWT.java
index 7b9130188..cd03454c8 100644
--- a/src/newt/classes/com/jogamp/newt/awt/NewtFactoryAWT.java
+++ b/src/newt/classes/com/jogamp/newt/awt/NewtFactoryAWT.java
@@ -51,7 +51,7 @@ public class NewtFactoryAWT extends NewtFactory {
    *
    * @param awtCompObject must be of type java.awt.Component
    */
-  public static NativeWindow getNativeWindow(Object awtCompObject, Capabilities capsRequested) {
+  public static NativeWindow getNativeWindow(Object awtCompObject, CapabilitiesImmutable capsRequested) {
       if(null==awtCompObject) {
         throw new NativeWindowException("Null AWT Component");
       }
@@ -61,9 +61,8 @@ public class NewtFactoryAWT extends NewtFactory {
       return getNativeWindow( (java.awt.Component) awtCompObject, capsRequested );
   }
 
-  public static NativeWindow getNativeWindow(java.awt.Component awtComp, Capabilities capsRequested) {
-      DefaultGraphicsConfiguration config = 
-          AWTGraphicsConfiguration.create(awtComp, (Capabilities) capsRequested.clone(), capsRequested);
+  public static NativeWindow getNativeWindow(java.awt.Component awtComp, CapabilitiesImmutable capsRequested) {
+      DefaultGraphicsConfiguration config = AWTGraphicsConfiguration.create(awtComp, capsRequested, capsRequested);
       NativeWindow awtNative = NativeWindowFactory.getNativeWindow(awtComp, config); // a JAWTWindow
       if(DEBUG_IMPLEMENTATION) {
         System.err.println("NewtFactoryAWT.getNativeWindow: "+awtComp+" -> "+awtNative);
diff --git a/src/newt/classes/com/jogamp/newt/impl/OffscreenWindow.java b/src/newt/classes/com/jogamp/newt/impl/OffscreenWindow.java
index 30dc945db..6e827dd77 100644
--- a/src/newt/classes/com/jogamp/newt/impl/OffscreenWindow.java
+++ b/src/newt/classes/com/jogamp/newt/impl/OffscreenWindow.java
@@ -50,11 +50,12 @@ public class OffscreenWindow extends WindowImpl implements SurfaceChangeable {
         if(0!=getParentWindowHandle()) {
             throw new NativeWindowException("OffscreenWindow does not support window parenting");
         }
-        if(caps.isOnscreen()) {
+        if(capsRequested.isOnscreen()) {
             throw new NativeWindowException("Capabilities is onscreen");
         }
         AbstractGraphicsScreen aScreen = getScreen().getGraphicsScreen();
-        config = GraphicsConfigurationFactory.getFactory(aScreen.getDevice()).chooseGraphicsConfiguration(caps, null, aScreen);
+        config = GraphicsConfigurationFactory.getFactory(aScreen.getDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, aScreen);
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
diff --git a/src/newt/classes/com/jogamp/newt/impl/WindowImpl.java b/src/newt/classes/com/jogamp/newt/impl/WindowImpl.java
index 572ed5bb7..30b17c575 100644
--- a/src/newt/classes/com/jogamp/newt/impl/WindowImpl.java
+++ b/src/newt/classes/com/jogamp/newt/impl/WindowImpl.java
@@ -56,7 +56,6 @@ import java.util.ArrayList;
 import java.lang.reflect.Method;
 import javax.media.nativewindow.AbstractGraphicsConfiguration;
 import javax.media.nativewindow.AbstractGraphicsDevice;
-import javax.media.nativewindow.Capabilities;
 import javax.media.nativewindow.CapabilitiesImmutable;
 import javax.media.nativewindow.NativeSurface;
 import javax.media.nativewindow.NativeWindow;
@@ -79,7 +78,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
     private NativeWindow parentWindow;
     private long parentWindowHandle;
     protected AbstractGraphicsConfiguration config;
-    protected Capabilities caps;
+    protected CapabilitiesImmutable capsRequested;
     protected boolean fullscreen, visible, hasFocus;
     protected int width, height, x, y;
     protected int nfs_width, nfs_height, nfs_x, nfs_y; // non fullscreen dimensions ..
@@ -165,7 +164,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
         return windowClass;
     }
 
-    public static WindowImpl create(NativeWindow parentWindow, long parentWindowHandle, Screen screen, Capabilities caps) {
+    public static WindowImpl create(NativeWindow parentWindow, long parentWindowHandle, Screen screen, CapabilitiesImmutable caps) {
         try {
             Class windowClass;
             if(caps.isOnscreen()) {
@@ -178,7 +177,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
             window.parentWindow = parentWindow;
             window.parentWindowHandle = parentWindowHandle;
             window.screen = (ScreenImpl) screen;
-            window.caps = (Capabilities)caps.clone();
+            window.capsRequested = (CapabilitiesImmutable) caps.cloneMutable();
             window.setUndecorated(0!=parentWindowHandle);
             return window;
         } catch (Throwable t) {
@@ -187,7 +186,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
         }
     }
 
-    public static WindowImpl create(Object[] cstrArguments, Screen screen, Capabilities caps) {
+    public static WindowImpl create(Object[] cstrArguments, Screen screen, CapabilitiesImmutable caps) {
         try {
             Class windowClass = getWindowClass(screen.getDisplay().getType());
             Class[] cstrArgumentTypes = getCustomConstructorArgumentTypes(windowClass);
@@ -201,7 +200,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
             WindowImpl window = (WindowImpl) ReflectionUtil.createInstance( windowClass, cstrArgumentTypes, cstrArguments ) ;
             window.initializeStates();
             window.screen = (ScreenImpl) screen;
-            window.caps = (Capabilities)caps.clone();
+            window.capsRequested = (CapabilitiesImmutable) caps.cloneMutable();
             return window;
         } catch (Throwable t) {
             throw new NativeWindowException(t);
@@ -825,7 +824,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
 
                 parentWindowHandle = 0;
                 parentWindow = null;
-                caps = null;
+                capsRequested = null;
                 lifecycleHook = null;
 
                 // Default position and dimension will be re-set immediately by user
@@ -1151,7 +1150,7 @@ public abstract class WindowImpl implements Window, NEWTEventConsumer, ScreenMod
     }
 
     public final CapabilitiesImmutable getRequestedCapabilities() {
-        return caps;
+        return capsRequested;
     }
 
     public String getTitle() {
diff --git a/src/newt/classes/com/jogamp/newt/impl/awt/AWTCanvas.java b/src/newt/classes/com/jogamp/newt/impl/awt/AWTCanvas.java
index 4b30e10b6..169b7bc3a 100644
--- a/src/newt/classes/com/jogamp/newt/impl/awt/AWTCanvas.java
+++ b/src/newt/classes/com/jogamp/newt/impl/awt/AWTCanvas.java
@@ -50,11 +50,11 @@ public class AWTCanvas extends Canvas {
   private GraphicsConfiguration chosen;
   private AWTGraphicsConfiguration awtConfig;
 
-  private Capabilities capabilities;
+  private CapabilitiesImmutable capabilities;
 
   private boolean displayConfigChanged=false;
 
-  public AWTCanvas(Capabilities capabilities) {
+  public AWTCanvas(CapabilitiesImmutable capabilities) {
     super();
 
     if(null==capabilities) {
@@ -86,7 +86,7 @@ public class AWTCanvas extends Canvas {
     /*
      * Save the chosen capabilities for use in getGraphicsConfiguration().
      */
-    awtConfig = chooseGraphicsConfiguration(capabilities, device);
+    awtConfig = chooseGraphicsConfiguration(capabilities, capabilities, device);
     if(Window.DEBUG_IMPLEMENTATION) {
         Exception e = new Exception("Info: Created Config: "+awtConfig);
         e.printStackTrace();
@@ -174,7 +174,7 @@ public class AWTCanvas extends Canvas {
          * block, both devices should have the same visual list, and the
          * same configuration should be selected here.
          */
-        AWTGraphicsConfiguration config = chooseGraphicsConfiguration((Capabilities)awtConfig.getRequestedCapabilities(), gc.getDevice());
+        AWTGraphicsConfiguration config = chooseGraphicsConfiguration(awtConfig.getChosenCapabilities(), awtConfig.getRequestedCapabilities(), gc.getDevice());
         final GraphicsConfiguration compatible = (null!=config)?config.getGraphicsConfiguration():null;
         if(Window.DEBUG_IMPLEMENTATION) {
             Exception e = new Exception("Info: Call Stack: "+Thread.currentThread().getName());
@@ -225,13 +225,13 @@ public class AWTCanvas extends Canvas {
     return gc;
   }
 
-  private static AWTGraphicsConfiguration chooseGraphicsConfiguration(Capabilities capabilities,
+  private static AWTGraphicsConfiguration chooseGraphicsConfiguration(CapabilitiesImmutable capsChosen,
+                                                                      CapabilitiesImmutable capsRequested,
                                                                       GraphicsDevice device) {
     AbstractGraphicsScreen aScreen = AWTGraphicsScreen.createScreenDevice(device, AbstractGraphicsDevice.DEFAULT_UNIT);
     AWTGraphicsConfiguration config = (AWTGraphicsConfiguration)
-      GraphicsConfigurationFactory.getFactory(AWTGraphicsDevice.class).chooseGraphicsConfiguration(capabilities,
-                                                                                                   null,
-                                                                                                   aScreen);
+      GraphicsConfigurationFactory.getFactory(AWTGraphicsDevice.class).chooseGraphicsConfiguration(capsChosen, capsRequested,
+                                                                                                   null, aScreen);
     if (config == null) {
       throw new NativeWindowException("Error: Couldn't fetch AWTGraphicsConfiguration");
     }
diff --git a/src/newt/classes/com/jogamp/newt/impl/awt/AWTWindow.java b/src/newt/classes/com/jogamp/newt/impl/awt/AWTWindow.java
index edd851451..7aa5874c4 100644
--- a/src/newt/classes/com/jogamp/newt/impl/awt/AWTWindow.java
+++ b/src/newt/classes/com/jogamp/newt/impl/awt/AWTWindow.java
@@ -119,7 +119,7 @@ public class AWTWindow extends WindowImpl {
                         frame.setTitle(getTitle());
                     }
                     container.setLayout(new BorderLayout());
-                    canvas = new AWTCanvas(caps);
+                    canvas = new AWTCanvas(capsRequested);
 
                     addWindowListener(new LocalWindowListener());
 
diff --git a/src/newt/classes/com/jogamp/newt/impl/intel/gdl/Window.java b/src/newt/classes/com/jogamp/newt/impl/intel/gdl/Window.java
index 749be8506..613d9eb02 100644
--- a/src/newt/classes/com/jogamp/newt/impl/intel/gdl/Window.java
+++ b/src/newt/classes/com/jogamp/newt/impl/intel/gdl/Window.java
@@ -53,7 +53,7 @@ public class Window extends com.jogamp.newt.impl.WindowImpl {
         AbstractGraphicsScreen aScreen = getScreen().getGraphicsScreen();
         AbstractGraphicsDevice aDevice = getScreen().getDisplay().getGraphicsDevice();
 
-        config = GraphicsConfigurationFactory.getFactory(aDevice).chooseGraphicsConfiguration(caps, null, aScreen);
+        config = GraphicsConfigurationFactory.getFactory(aDevice).chooseGraphicsConfiguration(capsRequested, capsRequested, null, aScreen);
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
diff --git a/src/newt/classes/com/jogamp/newt/impl/macosx/MacWindow.java b/src/newt/classes/com/jogamp/newt/impl/macosx/MacWindow.java
index 59b41c2aa..3d1f52eed 100644
--- a/src/newt/classes/com/jogamp/newt/impl/macosx/MacWindow.java
+++ b/src/newt/classes/com/jogamp/newt/impl/macosx/MacWindow.java
@@ -143,7 +143,8 @@ public class MacWindow extends WindowImpl {
     }
     
     protected void createNativeImpl() {
-        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(caps, null, getScreen().getGraphicsScreen());
+        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, getScreen().getGraphicsScreen());
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
diff --git a/src/newt/classes/com/jogamp/newt/impl/opengl/broadcom/egl/Window.java b/src/newt/classes/com/jogamp/newt/impl/opengl/broadcom/egl/Window.java
index ad903731b..6548cf6c4 100644
--- a/src/newt/classes/com/jogamp/newt/impl/opengl/broadcom/egl/Window.java
+++ b/src/newt/classes/com/jogamp/newt/impl/opengl/broadcom/egl/Window.java
@@ -35,9 +35,9 @@ package com.jogamp.newt.impl.opengl.broadcom.egl;
 
 import com.jogamp.opengl.impl.egl.*;
 import javax.media.nativewindow.*;
-import javax.media.opengl.GLCapabilities;
 import javax.media.nativewindow.NativeWindowException;
 import javax.media.nativewindow.util.Point;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class Window extends com.jogamp.newt.impl.WindowImpl {
     static {
@@ -53,7 +53,8 @@ public class Window extends com.jogamp.newt.impl.WindowImpl {
         }
         // query a good configuration .. even thought we drop this one 
         // and reuse the EGLUtil choosen one later.
-        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(caps, null, getScreen().getGraphicsScreen());
+        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, getScreen().getGraphicsScreen());
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
@@ -149,7 +150,7 @@ public class Window extends com.jogamp.newt.impl.WindowImpl {
     private void windowCreated(int cfgID, int width, int height) {
         this.width = width;
         this.height = height;
-        GLCapabilities capsReq = (GLCapabilities) config.getRequestedCapabilities();
+        GLCapabilitiesImmutable capsReq = (GLCapabilitiesImmutable) config.getRequestedCapabilities();
         config = EGLGraphicsConfiguration.create(capsReq, getScreen().getGraphicsScreen(), cfgID);
         if (config == null) {
             throw new NativeWindowException("Error creating EGLGraphicsConfiguration from id: "+cfgID+", "+this);
diff --git a/src/newt/classes/com/jogamp/newt/impl/opengl/kd/KDWindow.java b/src/newt/classes/com/jogamp/newt/impl/opengl/kd/KDWindow.java
index f0bc8587b..eb03dc9dc 100644
--- a/src/newt/classes/com/jogamp/newt/impl/opengl/kd/KDWindow.java
+++ b/src/newt/classes/com/jogamp/newt/impl/opengl/kd/KDWindow.java
@@ -33,15 +33,12 @@
 
 package com.jogamp.newt.impl.opengl.kd;
 
-import com.jogamp.newt.*;
-import com.jogamp.newt.event.*;
 import com.jogamp.newt.impl.*;
 import com.jogamp.opengl.impl.egl.*;
 import javax.media.nativewindow.*;
-import javax.media.opengl.GLCapabilities;
-import javax.media.opengl.GLProfile;
 import javax.media.nativewindow.NativeWindowException;
 import javax.media.nativewindow.util.Point;
+import javax.media.opengl.GLCapabilitiesImmutable;
 
 public class KDWindow extends WindowImpl {
     private static final String WINDOW_CLASS_NAME = "NewtWindow";
@@ -57,12 +54,13 @@ public class KDWindow extends WindowImpl {
         if(0!=getParentWindowHandle()) {
             throw new RuntimeException("Window parenting not supported (yet)");
         }
-        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(caps, null, getScreen().getGraphicsScreen());
+        config = GraphicsConfigurationFactory.getFactory(getScreen().getDisplay().getGraphicsDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, getScreen().getGraphicsScreen());
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
 
-        GLCapabilities eglCaps = (GLCapabilities)config.getChosenCapabilities();
+        GLCapabilitiesImmutable eglCaps = (GLCapabilitiesImmutable) config.getChosenCapabilities();
         int[] eglAttribs = EGLGraphicsConfiguration.GLCapabilities2AttribList(eglCaps);
 
         eglWindowHandle = CreateWindow(getDisplayHandle(), eglAttribs);
diff --git a/src/newt/classes/com/jogamp/newt/impl/windows/WindowsWindow.java b/src/newt/classes/com/jogamp/newt/impl/windows/WindowsWindow.java
index 2c3ffc3cc..b188a580e 100644
--- a/src/newt/classes/com/jogamp/newt/impl/windows/WindowsWindow.java
+++ b/src/newt/classes/com/jogamp/newt/impl/windows/WindowsWindow.java
@@ -92,7 +92,8 @@ public class WindowsWindow extends WindowImpl {
     protected void createNativeImpl() {
         WindowsScreen  screen = (WindowsScreen) getScreen();
         WindowsDisplay display = (WindowsDisplay) screen.getDisplay();
-        config = GraphicsConfigurationFactory.getFactory(display.getGraphicsDevice()).chooseGraphicsConfiguration(caps, null, screen.getGraphicsScreen());
+        config = GraphicsConfigurationFactory.getFactory(display.getGraphicsDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, screen.getGraphicsScreen());
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
diff --git a/src/newt/classes/com/jogamp/newt/impl/x11/X11Window.java b/src/newt/classes/com/jogamp/newt/impl/x11/X11Window.java
index 91143923d..e81acee3e 100644
--- a/src/newt/classes/com/jogamp/newt/impl/x11/X11Window.java
+++ b/src/newt/classes/com/jogamp/newt/impl/x11/X11Window.java
@@ -52,7 +52,8 @@ public class X11Window extends WindowImpl {
     protected void createNativeImpl() {
         X11Screen screen = (X11Screen) getScreen();
         X11Display display = (X11Display) screen.getDisplay();
-        config = GraphicsConfigurationFactory.getFactory(display.getGraphicsDevice()).chooseGraphicsConfiguration(caps, null, screen.getGraphicsScreen());
+        config = GraphicsConfigurationFactory.getFactory(display.getGraphicsDevice()).chooseGraphicsConfiguration(
+                capsRequested, capsRequested, null, screen.getGraphicsScreen());
         if (config == null) {
             throw new NativeWindowException("Error choosing GraphicsConfiguration creating window: "+this);
         }
diff --git a/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java b/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
index 967836cf6..d6da09bec 100644
--- a/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
+++ b/src/newt/classes/com/jogamp/newt/opengl/GLWindow.java
@@ -35,7 +35,6 @@
 package com.jogamp.newt.opengl;
 
 import com.jogamp.common.GlueGenVersion;
-import com.jogamp.common.util.VersionUtil;
 import com.jogamp.nativewindow.NativeWindowVersion;
 import com.jogamp.newt.*;
 import com.jogamp.newt.event.*;
@@ -101,7 +100,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
      * <P>
      * The resulting GLWindow owns the Window, Screen and Device, ie it will be destructed.
      */
-    public static GLWindow create(GLCapabilities caps) {
+    public static GLWindow create(GLCapabilitiesImmutable caps) {
         return new GLWindow(NewtFactory.createWindow(caps));
     }
 
@@ -111,7 +110,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
      * <P>
      * The resulting GLWindow owns the Window, ie it will be destructed.
      */
-    public static GLWindow create(Screen screen, GLCapabilities caps) {
+    public static GLWindow create(Screen screen, GLCapabilitiesImmutable caps) {
         return new GLWindow(NewtFactory.createWindow(screen, caps));
     }
 
@@ -133,7 +132,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
      * <P>
      * The resulting GLWindow owns the Window, ie it will be destructed. 
      */
-    public static GLWindow create(NativeWindow parentNativeWindow, GLCapabilities caps) {
+    public static GLWindow create(NativeWindow parentNativeWindow, GLCapabilitiesImmutable caps) {
         return new GLWindow(NewtFactory.createWindow(parentNativeWindow, caps));
     }
 
@@ -359,7 +358,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
                 } else {
                     nw = window;
                 }
-                GLCapabilities glCaps = (GLCapabilities) nw.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
+                GLCapabilitiesImmutable glCaps = (GLCapabilitiesImmutable) nw.getGraphicsConfiguration().getNativeGraphicsConfiguration().getChosenCapabilities();
                 if(null==factory) {
                     factory = GLDrawableFactory.getFactory(glCaps.getGLProfile());
                 }
@@ -670,7 +669,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
         return ( null != drawable ) ? drawable.isRealized() : false;
     }
 
-    public final GLCapabilities getChosenGLCapabilities() {
+    public final GLCapabilitiesImmutable getChosenGLCapabilities() {
         if (drawable == null) {
             throw new GLException("No drawable yet");
         }
@@ -863,7 +862,7 @@ public class GLWindow implements GLAutoDrawable, Window, NEWTEventConsumer {
         System.err.println(NativeWindowVersion.getInstance());
         System.err.print(JoglVersion.getInstance());
         System.err.println(NewtVersion.getInstance());
-        GLCapabilities caps = new GLCapabilities( GLProfile.getDefault() );
+        GLCapabilitiesImmutable caps = new GLCapabilities( GLProfile.getDefault() );
 
         GLWindow glWindow = GLWindow.create(caps);
         glWindow.setSize(128, 128);