GraphUI: Adopting Vec*f API; Adding Group; Scene + Group are Container, traversing the PMVMatrix throughout childs (-> see TreeTool).

Utilizing the Vec*f (and Matrix4f) API w/ AABBox et al renders our code more clean & safe,
see commit 15e60161787224e85172685f74dc0ac195969b51.

A Group allows to contain multiple Shapes,
hence the PMVMatrix must be traversed accordingly using TreeTool
for all operations (draw, picking, win->obj coordinates, ..).

Hence Scene + Group are now implementing Container
and reuse code via TreeTool and a Shape.Visitor*.

This will allow further simplification of user code.

10 files changed, 913 insertions, 214 deletions

diff --git a/src/graphui/classes/com/jogamp/graph/ui/Container.java b/src/graphui/classes/com/jogamp/graph/ui/Container.java
new file mode 100644
index 000000000..e48476fcf
--- /dev/null
+++ b/src/graphui/classes/com/jogamp/graph/ui/Container.java
@@ -0,0 +1,97 @@
+/**
+ * Copyright 2023 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 com.jogamp.graph.ui;
+
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+
+import com.jogamp.graph.ui.Shape.Visitor2;
+import com.jogamp.graph.ui.Shape.Visitor1;
+import com.jogamp.opengl.fixedfunc.GLMatrixFunc;
+import com.jogamp.opengl.math.geom.AABBox;
+import com.jogamp.opengl.util.PMVMatrix;
+
+/**
+ * Container interface of UI {@link Shape}s
+ * @see Scene
+ * @see Shape
+ */
+public interface Container {
+
+    List<Shape> getShapes();
+
+    void addShape(Shape s);
+
+    /** Removes given shape, , w/o {@link Shape#destroy(com.jogamp.opengl.GL2ES2, com.jogamp.graph.curve.opengl.RegionRenderer) destroying} them. */
+    void removeShape(Shape s);
+
+    void addShapes(Collection<? extends Shape> shapes);
+
+    /** Removes all given shapes, w/o {@link Shape#destroy(com.jogamp.opengl.GL2ES2, com.jogamp.graph.curve.opengl.RegionRenderer) destroying} them. */
+    void removeShapes(Collection<? extends Shape> shapes);
+
+    boolean contains(Shape s);
+
+    AABBox getBounds(final PMVMatrix pmv, Shape shape);
+
+    /**
+     * Traverses through the graph up until {@code shape} and apply {@code action} on it.
+     * @param pmv
+     * @param shape
+     * @param action
+     * @return true to signal operation complete, i.e. {@code shape} found, otherwise false
+     */
+    boolean forOne(final PMVMatrix pmv, final Shape shape, final Runnable action);
+
+    /**
+     * Traverses through the graph and apply {@link Visitor1#visit(Shape)} for each, stop if it returns true.
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor1#visit(Shape)} returned true, otherwise false
+     */
+    boolean forAll(Visitor1 v);
+
+    /**
+     * Traverses through the graph and apply {@link Visitor2#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    boolean forAll(final PMVMatrix pmv, Visitor2 v);
+
+    /**
+     * Traverses through the graph and apply {@link Visitor#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     *
+     * Each {@link Container} level is sorted using {@code sortComp}
+     * @param sortComp
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    boolean forSortedAll(final Comparator<Shape> sortComp, final PMVMatrix pmv, final Visitor2 v);
+}
\ No newline at end of file
diff --git a/src/graphui/classes/com/jogamp/graph/ui/GraphShape.java b/src/graphui/classes/com/jogamp/graph/ui/GraphShape.java
index 6efd7f5f4..8b142210a 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/GraphShape.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/GraphShape.java
@@ -38,7 +38,6 @@ import com.jogamp.graph.geom.Vertex;
 import com.jogamp.graph.geom.Vertex.Factory;
 import com.jogamp.opengl.GL2ES2;
 import com.jogamp.opengl.GLProfile;
-import com.jogamp.opengl.math.geom.AABBox;
 import com.jogamp.opengl.util.texture.TextureSequence;
 
 /**
@@ -137,7 +136,7 @@ public abstract class GraphShape extends Shape {
         if( null != gl ) {
             clearDirtyRegions(gl);
         }
-        if( isShapeDirty() || null == region ) {
+        if( isShapeDirty() ) {
             if( null == region ) {
                 region = createGLRegion(glp);
             } else if( null == gl ) {
@@ -164,7 +163,7 @@ public abstract class GraphShape extends Shape {
         final float x2 = box.getMaxX();
         final float y1 = box.getMinY();
         final float y2 = box.getMaxY();
-        final float z = box.getCenter()[2]; // 0; // box.getMinZ() + 0.025f;
+        final float z = box.getCenter().z(); // 0; // box.getMinZ() + 0.025f;
         {
             // Outer OutlineShape as Winding.CCW.
             shape.moveTo(x1, y1, z);
diff --git a/src/graphui/classes/com/jogamp/graph/ui/Group.java b/src/graphui/classes/com/jogamp/graph/ui/Group.java
new file mode 100644
index 000000000..8174b279c
--- /dev/null
+++ b/src/graphui/classes/com/jogamp/graph/ui/Group.java
@@ -0,0 +1,249 @@
+/**
+ * Copyright 2023 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 com.jogamp.graph.ui;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Comparator;
+import java.util.List;
+
+import com.jogamp.graph.curve.opengl.GLRegion;
+import com.jogamp.graph.curve.opengl.RegionRenderer;
+import com.jogamp.opengl.GL2ES2;
+import com.jogamp.opengl.GLProfile;
+import com.jogamp.opengl.math.geom.AABBox;
+import com.jogamp.opengl.util.PMVMatrix;
+
+import jogamp.graph.ui.TreeTool;
+
+/**
+ * Group of UI {@link Shape}s, optionally utilizing a {@link Group.Layout}.
+ * @see Scene
+ * @see Shape
+ * @see Group.Layout
+ */
+public class Group extends Shape implements Container {
+    /** Layout for the group, called @ {@link Group#validate(GL2ES2)} or {@link Group#validate(GLProfile)}.  */
+    public static interface Layout {
+        /** Performing the layout, called @ {@link Group#validate(GL2ES2)} or {@link Group#validate(GLProfile)}. */
+        void layout(Group g);
+    }
+
+    private final List<Shape> shapes = new ArrayList<Shape>();
+    private Layout layouter;
+
+    /**
+     * Create a Graph based {@link GLRegion} UI {@link Shape}.
+     */
+    public Group() {
+        super();
+    }
+
+    /**
+     * Create a Graph based {@link GLRegion} UI {@link Shape} w/ given {@link Group.Layour}.
+     */
+    public Group(final Layout l) {
+        super();
+        this.layouter = l;
+    }
+
+    /** Return current {@link Group.Layout}. */
+    public Layout getLayour() { return layouter; }
+
+    /** Set {@link Group.Layout}. */
+    public void setLayout(final Layout l) { layouter = l; }
+
+    @Override
+    public List<Shape> getShapes() {
+        return shapes;
+    }
+    @Override
+    public void addShape(final Shape s) {
+        shapes.add(s);
+    }
+
+    /** Removes given shape, keeps it alive. */
+    @Override
+    public void removeShape(final Shape s) {
+        shapes.remove(s);
+    }
+
+    /** Removes all given shapes and destroys them. */
+    public void removeShape(final GL2ES2 gl, final RegionRenderer renderer, final Shape s) {
+        s.setDebugBox(0f);
+        shapes.remove(s);
+        s.destroy(gl, renderer);
+    }
+
+    @Override
+    public void addShapes(final Collection<? extends Shape> shapes) {
+        for(final Shape s : shapes) {
+            addShape(s);
+        }
+    }
+    /** Removes all given shapes, keeps them alive. */
+    @Override
+    public void removeShapes(final Collection<? extends Shape> shapes) {
+        for(final Shape s : shapes) {
+            removeShape(s);
+        }
+    }
+    /** Removes all given shapes and destroys them. */
+    public void removeShapes(final GL2ES2 gl, final RegionRenderer renderer, final Collection<? extends Shape> shapes) {
+        for(final Shape s : shapes) {
+            removeShape(gl, renderer, s);
+        }
+    }
+
+    @Override
+    public boolean hasColorChannel() {
+        return false; // FIXME
+    }
+
+    @Override
+    protected final void clearImpl0(final GL2ES2 gl, final RegionRenderer renderer) {
+        for(final Shape s : shapes) {
+            // s.clearImpl0(gl, renderer);;
+            s.clear(gl, renderer);;
+        }
+    }
+
+    @Override
+    protected final void destroyImpl0(final GL2ES2 gl, final RegionRenderer renderer) {
+        for(final Shape s : shapes) {
+            // s.destroyImpl0(gl, renderer);
+            s.destroy(gl, renderer);;
+        }
+    }
+
+    private void layout() {
+        if( null != layouter ) {
+            layouter.layout(this);
+        }
+    }
+
+    private final boolean doFrustumCulling = true; // FIXME
+
+    @Override
+    protected final void drawImpl0(final GL2ES2 gl, final RegionRenderer renderer, final int[] sampleCount, final float[] rgba) {
+        final PMVMatrix pmv = renderer.getMatrix();
+        final int shapeCount = shapes.size();
+        for(int i=0; i<shapeCount; i++) {
+            final Shape shape = shapes.get(i);
+            if( shape.isEnabled() ) {
+                pmv.glPushMatrix();
+                shape.setTransform(pmv);
+
+                if( !doFrustumCulling || !pmv.glGetFrustum().isAABBoxOutside( shape.getBounds() ) ) {
+                    if( null == rgba ) {
+                        shape.drawToSelect(gl, renderer, sampleCount);
+                    } else {
+                        shape.draw(gl, renderer, sampleCount);
+                    }
+                }
+                pmv.glPopMatrix();
+            }
+        }
+    }
+
+    @Override
+    protected void validateImpl(final GLProfile glp, final GL2ES2 gl) {
+        if( isShapeDirty() ) {
+            layout();
+            final PMVMatrix pmv = new PMVMatrix();
+            final AABBox tmpBox = new AABBox();
+            final float[] vec3Tmp0 = new float[3];
+            final float[] vec3Tmp1 = new float[3];
+            for(final Shape s : shapes) {
+                // s.validateImpl(glp, gl);
+                if( null != gl ) {
+                    s.validate(gl);
+                } else {
+                    s.validate(glp);
+                }
+                pmv.glPushMatrix();
+                s.setTransform(pmv);
+                s.getBounds().transformMv(tmpBox, pmv, vec3Tmp0, vec3Tmp0);
+                pmv.glPopMatrix();
+                box.resize(tmpBox);
+            }
+        }
+    }
+
+    @Override
+    public boolean contains(final Shape s) {
+        if( shapes.contains(s) ) {
+            return true;
+        }
+        for(final Shape shape : shapes) {
+            if( shape instanceof Container ) {
+                if( ((Container)shape).contains(s) ) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    @Override
+    public AABBox getBounds(final PMVMatrix pmv, final Shape shape) {
+        pmv.reset();
+        setTransform(pmv);
+        final AABBox res = new AABBox();
+        if( null == shape ) {
+            return res;
+        }
+        final float[] vec3Tmp0 = new float[3];
+        final float[] vec3Tmp1 = new float[3];
+        forOne(pmv, shape, () -> {
+            shape.getBounds().transformMv(res, pmv, vec3Tmp0, vec3Tmp1);
+        });
+        return res;
+    }
+
+    @Override
+    public boolean forOne(final PMVMatrix pmv, final Shape shape, final Runnable action) {
+        return TreeTool.forOne(shapes, pmv, shape, action);
+    }
+
+    @Override
+    public boolean forAll(final Visitor1 v) {
+        return TreeTool.forAll(shapes, v);
+    }
+
+    @Override
+    public boolean forAll(final PMVMatrix pmv, final Visitor2 v) {
+        return TreeTool.forAll(shapes, pmv, v);
+    }
+
+    @Override
+    public boolean forSortedAll(final Comparator<Shape> sortComp, final PMVMatrix pmv, final Visitor2 v) {
+        return TreeTool.forSortedAll(sortComp, shapes, pmv, v);
+    }
+}
+
diff --git a/src/graphui/classes/com/jogamp/graph/ui/Scene.java b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
index 831a9d334..ac3bbe146 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/Scene.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
@@ -49,6 +49,8 @@ import com.jogamp.common.nio.Buffers;
 import com.jogamp.graph.curve.Region;
 import com.jogamp.graph.curve.opengl.RegionRenderer;
 import com.jogamp.graph.curve.opengl.RenderState;
+import com.jogamp.graph.ui.Shape.Visitor2;
+import com.jogamp.graph.ui.Shape.Visitor1;
 import com.jogamp.newt.event.GestureHandler;
 import com.jogamp.newt.event.InputEvent;
 import com.jogamp.newt.event.MouseEvent;
@@ -58,11 +60,14 @@ import com.jogamp.newt.event.GestureHandler.GestureEvent;
 import com.jogamp.newt.opengl.GLWindow;
 import com.jogamp.opengl.math.FloatUtil;
 import com.jogamp.opengl.math.Ray;
+import com.jogamp.opengl.math.Vec3f;
 import com.jogamp.opengl.math.geom.AABBox;
 import com.jogamp.opengl.util.GLPixelStorageModes;
 import com.jogamp.opengl.util.GLReadBufferUtil;
 import com.jogamp.opengl.util.PMVMatrix;
 
+import jogamp.graph.ui.TreeTool;
+
 /**
  * GraphUI Scene
  * <p>
@@ -86,7 +91,7 @@ import com.jogamp.opengl.util.PMVMatrix;
  * </p>
  * @see Shape
  */
-public final class Scene implements GLEventListener {
+public final class Scene implements Container, GLEventListener {
     /** Default scene distance on z-axis to projection is -1/5f. */
     public static final float DEFAULT_SCENE_DIST = -1/5f;
     /** Default projection angle in degrees value is 45.0. */
@@ -201,14 +206,16 @@ public final class Scene implements GLEventListener {
         }
     }
 
+    @Override
     public List<Shape> getShapes() {
         return shapes;
     }
+    @Override
     public void addShape(final Shape s) {
         s.setDebugBox(dbgbox_thickness);
         shapes.add(s);
     }
-    /** Removes given shape, keeps it alive. */
+    @Override
     public void removeShape(final Shape s) {
         s.setDebugBox(0f);
         shapes.remove(s);
@@ -219,12 +226,13 @@ public final class Scene implements GLEventListener {
         shapes.remove(s);
         s.destroy(gl, renderer);
     }
+    @Override
     public void addShapes(final Collection<? extends Shape> shapes) {
         for(final Shape s : shapes) {
             addShape(s);
         }
     }
-    /** Removes all given shapes, keeps them alive. */
+    @Override
     public void removeShapes(final Collection<? extends Shape> shapes) {
         for(final Shape s : shapes) {
             removeShape(s);
@@ -236,6 +244,10 @@ public final class Scene implements GLEventListener {
             removeShape(gl, s);
         }
     }
+    @Override
+    public boolean contains(final Shape s) {
+        return false;
+    }
     public Shape getShapeByIdx(final int id) {
         if( 0 > id ) {
             return null;
@@ -449,17 +461,9 @@ public final class Scene implements GLEventListener {
      * @param runnable the action to perform if {@link Shape} was found
      * @return picked Shape if any or null as stored in {@code shape}
      */
-    public Shape pickShape(final PMVMatrix pmv, final int glWinX, final int glWinY, final float[] objPos, final Shape[] shape, final Runnable runnable) {
+    public Shape pickShape(final PMVMatrix pmv, final int glWinX, final int glWinY, final Vec3f objPos, final Shape[] shape, final Runnable runnable) {
         setupMatrix(pmv);
-        final Shape pick = pickShapeImpl(pmv, glWinX, glWinY, objPos);
-        shape[0] = pick;
-        if( null != pick ) {
-            runnable.run();
-        }
-        return pick;
-    }
-    @SuppressWarnings({ "unchecked", "rawtypes" })
-    private Shape pickShapeImpl(final PMVMatrix pmv, final int glWinX, final int glWinY, final float[] objPos) {
+
         final float winZ0 = 0f;
         final float winZ1 = 0.3f;
         /**
@@ -467,34 +471,28 @@ public final class Scene implements GLEventListener {
             gl.glReadPixels( x, y, 1, 1, GL2ES2.GL_DEPTH_COMPONENT, GL.GL_FLOAT, winZRB);
             winZ1 = winZRB.get(0); // dir
         */
-
+        final int[] viewport = getViewport();
         final Ray ray = new Ray();
-
-        final Object[] shapesS = shapes.toArray();
-        Arrays.sort(shapesS, (Comparator)Shape.ZAscendingComparator);
-
-        for(int i=shapesS.length-1; i>=0; i--) {
-            final Shape uiShape = (Shape)shapesS[i];
-
-            if( uiShape.isEnabled() ) {
-                pmv.glPushMatrix();
-                uiShape.setTransform(pmv);
-                final boolean ok = pmv.gluUnProjectRay(glWinX, glWinY, winZ0, winZ1, getViewport(), 0, ray);
-                if( ok ) {
-                    final AABBox sbox = uiShape.getBounds();
-                    if( sbox.intersectsRay(ray) ) {
-                        // System.err.printf("Pick.0: shape %d, [%d, %d, %f/%f] -> %s%n", i, glWinX, glWinY, winZ0, winZ1, ray);
-                        if( null == sbox.getRayIntersection(objPos, ray, FloatUtil.EPSILON, true, dpyTmp1V3, dpyTmp2V3, dpyTmp3V3) ) {
-                            throw new InternalError("Ray "+ray+", box "+sbox);
-                        }
-                        // System.err.printf("Pick.1: shape %d @ [%f, %f, %f], within %s%n", i, objPos[0], objPos[1], objPos[2], uiShape.getBounds());
-                        return uiShape;
+        shape[0] = null;
+
+        forSortedAll(Shape.ZAscendingComparator, pmv, (final Shape s, final PMVMatrix pmv2) -> {
+            final boolean ok = pmv.gluUnProjectRay(glWinX, glWinY, winZ0, winZ1, viewport, ray);
+            if( ok ) {
+                final AABBox sbox = s.getBounds();
+                if( sbox.intersectsRay(ray) ) {
+                    // System.err.printf("Pick.0: shape %d, [%d, %d, %f/%f] -> %s%n", i, glWinX, glWinY, winZ0, winZ1, ray);
+                    if( null == sbox.getRayIntersection(objPos, ray, FloatUtil.EPSILON, true) ) {
+                        throw new InternalError("Ray "+ray+", box "+sbox);
                     }
+                    // System.err.printf("Pick.1: shape %d @ [%f, %f, %f], within %s%n", i, objPos[0], objPos[1], objPos[2], uiShape.getBounds());
+                    shape[0] = s;
+                    runnable.run();
+                    return true;
                 }
-                pmv.glPopMatrix(); // we leave the stack open if picked above, allowing the modelview shape transform to be reused
             }
-        }
-        return null;
+            return false;
+        });
+        return shape[0];
     }
     private final float[] dpyTmp1V3 = new float[3];
     private final float[] dpyTmp2V3 = new float[3];
@@ -514,7 +512,7 @@ public final class Scene implements GLEventListener {
      * @param shape storage for found {@link Shape} or null
      * @param runnable the action to perform if {@link Shape} was found
      */
-    public void pickShapeGL(final int glWinX, final int glWinY, final float[] objPos, final Shape[] shape, final Runnable runnable) {
+    public void pickShapeGL(final int glWinX, final int glWinY, final Vec3f objPos, final Shape[] shape, final Runnable runnable) {
         if( null == cDrawable ) {
             return;
         }
@@ -586,10 +584,79 @@ public final class Scene implements GLEventListener {
      * @param objPos resulting object position
      * @param runnable action
      */
-    public void winToShapeCoord(final Shape shape, final int glWinX, final int glWinY, final PMVMatrix pmv, final float[] objPos, final Runnable runnable) {
-        if( null != shape && null != shape.winToShapeCoord(pmvMatrixSetup, renderer.getViewport(), glWinX, glWinY, pmv, objPos) ) {
-            runnable.run();
+    public void winToShapeCoord(final Shape shape, final int glWinX, final int glWinY, final PMVMatrix pmv, final Vec3f objPos, final Runnable runnable) {
+        if( null == shape ) {
+            return;
         }
+        final int[] viewport = getViewport();
+        setupMatrix(pmv);
+        forOne(pmv, shape, () -> {
+            if( null != shape.winToShapeCoord(pmv, viewport, glWinX, glWinY, objPos) ) {
+                runnable.run();
+            }
+        });
+    }
+
+    @Override
+    public AABBox getBounds(final PMVMatrix pmv, final Shape shape) {
+        final AABBox res = new AABBox();
+        if( null == shape ) {
+            return res;
+        }
+        setupMatrix(pmv);
+        forOne(pmv, shape, () -> {
+            shape.getBounds().transformMv(res, pmv, new float[3], new float[3]);
+        });
+        return res;
+    }
+
+    /**
+     * Traverses through the graph up until {@code shape} and apply {@code action} on it.
+     * @param pmv
+     * @param shape
+     * @param action
+     * @return true to signal operation complete, i.e. {@code shape} found, otherwise false
+     */
+    @Override
+    public boolean forOne(final PMVMatrix pmv, final Shape shape, final Runnable action) {
+        setupMatrix(pmv);
+        return TreeTool.forOne(shapes, pmv, shape, action);
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor2#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    @Override
+    public boolean forAll(final PMVMatrix pmv, final Visitor2 v) {
+        setupMatrix(pmv);
+        return TreeTool.forAll(shapes, pmv, v);
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor1#visit(Shape)} for each, stop if it returns true.
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor1#visit(Shape)} returned true, otherwise false
+     */
+    @Override
+    public boolean forAll(final Visitor1 v) {
+        return TreeTool.forAll(shapes, v);
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     *
+     * Each {@link Container} level is sorted using {@code sortComp}
+     * @param sortComp
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    @Override
+    public boolean forSortedAll(final Comparator<Shape> sortComp, final PMVMatrix pmv, final Visitor2 v) {
+        return TreeTool.forSortedAll(sortComp, shapes, pmv, v);
     }
 
     /**
@@ -788,16 +855,18 @@ public final class Scene implements GLEventListener {
                 // gesture .. delegate to active shape!
                 final InputEvent orig = gh.getTrigger();
                 if( orig instanceof MouseEvent ) {
-                    final MouseEvent e = (MouseEvent) orig;
-                    // flip to GL window coordinates
-                    final int glWinX = e.getX();
-                    final int glWinY = getHeight() - e.getY() - 1;
-                    final PMVMatrix pmv = new PMVMatrix();
-                    final float[] objPos = new float[3];
                     final Shape shape = activeShape;
-                    winToShapeCoord(shape, glWinX, glWinY, pmv, objPos, () -> {
-                        shape.dispatchGestureEvent(gh, glWinX, glWinY, pmv, renderer.getViewport(), objPos);
-                    });
+                    if( shape.isInteractive() ) {
+                        final MouseEvent e = (MouseEvent) orig;
+                        // flip to GL window coordinates
+                        final int glWinX = e.getX();
+                        final int glWinY = getHeight() - e.getY() - 1;
+                        final PMVMatrix pmv = new PMVMatrix();
+                        final Vec3f objPos = new Vec3f();
+                        winToShapeCoord(shape, glWinX, glWinY, pmv, objPos, () -> {
+                            shape.dispatchGestureEvent(gh, glWinX, glWinY, pmv, renderer.getViewport(), objPos);
+                        });
+                    }
                 }
             }
         }
@@ -812,7 +881,7 @@ public final class Scene implements GLEventListener {
     final void dispatchMouseEvent(final MouseEvent e, final int glWinX, final int glWinY) {
         if( null == activeShape ) {
             dispatchMouseEventPickShape(e, glWinX, glWinY);
-        } else {
+        } else if( activeShape.isInteractive() ) {
             dispatchMouseEventForShape(activeShape, e, glWinX, glWinY);
         }
     }
@@ -824,11 +893,13 @@ public final class Scene implements GLEventListener {
      */
     final void dispatchMouseEventPickShape(final MouseEvent e, final int glWinX, final int glWinY) {
         final PMVMatrix pmv = new PMVMatrix();
-        final float[] objPos = new float[3];
+        final Vec3f objPos = new Vec3f();
         final Shape[] shape = { null };
         if( null == pickShape(pmv, glWinX, glWinY, objPos, shape, () -> {
                setActiveShape(shape[0]);
-               shape[0].dispatchMouseEvent(e, glWinX, glWinY, objPos);
+               if( shape[0].isInteractive() ) {
+                   shape[0].dispatchMouseEvent(e, glWinX, glWinY, objPos);
+               }
            } ) )
         {
            releaseActiveShape();
@@ -843,7 +914,7 @@ public final class Scene implements GLEventListener {
      */
     final void dispatchMouseEventForShape(final Shape shape, final MouseEvent e, final int glWinX, final int glWinY) {
         final PMVMatrix pmv = new PMVMatrix();
-        final float[] objPos = new float[3];
+        final Vec3f objPos = new Vec3f();
         winToShapeCoord(shape, glWinX, glWinY, pmv, objPos, () -> { shape.dispatchMouseEvent(e, glWinX, glWinY, objPos); });
     }
 
@@ -1059,4 +1130,5 @@ public final class Scene implements GLEventListener {
         }
     };
     private PMVMatrixSetup pmvMatrixSetup = defaultPMVMatrixSetup;
+
 }
diff --git a/src/graphui/classes/com/jogamp/graph/ui/Shape.java b/src/graphui/classes/com/jogamp/graph/ui/Shape.java
index dcac39504..658d7848d 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/Shape.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/Shape.java
@@ -44,7 +44,8 @@ import com.jogamp.newt.event.MouseEvent;
 import com.jogamp.newt.event.MouseListener;
 import com.jogamp.opengl.math.FloatUtil;
 import com.jogamp.opengl.math.Quaternion;
-import com.jogamp.opengl.math.VectorUtil;
+import com.jogamp.opengl.math.Vec2f;
+import com.jogamp.opengl.math.Vec3f;
 import com.jogamp.opengl.math.geom.AABBox;
 import com.jogamp.opengl.util.PMVMatrix;
 
@@ -67,6 +68,34 @@ import com.jogamp.opengl.util.PMVMatrix;
  * @see Scene
  */
 public abstract class Shape {
+    /**
+     * General {@link Shape} visitor
+     */
+    public static interface Visitor1 {
+        /**
+         * Visitor method
+         * @param s the {@link Shape} to process
+         * @return true to signal operation complete and to stop traversal, otherwise false
+         */
+        boolean visit(Shape s);
+    }
+
+    /**
+     * General {@link Shape} visitor
+     */
+    public static interface Visitor2 {
+        /**
+         * Visitor method
+         * @param s the {@link Shape} to process
+         * @param pmv the {@link PMVMatrix} setup from the {@link Scene} down to the {@link Shape}
+         * @return true to signal operation complete and to stop traversal, otherwise false
+         */
+        boolean visit(Shape s, final PMVMatrix pmv);
+    }
+
+    /**
+     * General {@link Shape} listener action
+     */
     public static interface Listener {
         void run(final Shape shape);
     }
@@ -78,10 +107,10 @@ public abstract class Shape {
 
     protected final AABBox box;
 
-    private final float[] position = new float[] { 0f, 0f, 0f };
+    private final Vec3f position = new Vec3f();
     private final Quaternion rotation = new Quaternion();
-    private final float[] rotPivot = new float[] { 0f, 0f, 0f };
-    private final float[] scale = new float[] { 1f, 1f, 1f };
+    private final Vec3f rotPivot = new Vec3f();
+    private final Vec3f scale = new Vec3f(1f, 1f, 1f);
 
     private volatile int dirty = DIRTY_SHAPE | DIRTY_STATE;
     private final Object dirtySync = new Object();
@@ -102,6 +131,7 @@ public abstract class Shape {
     private boolean toggleable = false;
     private boolean draggable = true;
     private boolean resizable = true;
+    private boolean interactive = true;
     private boolean enabled = true;
     private float dbgbox_thickness = 0f; // fractional thickness of bounds, 0f for no debug box
     private ArrayList<MouseGestureListener> mouseListeners = new ArrayList<MouseGestureListener>();
@@ -142,16 +172,10 @@ public abstract class Shape {
     public final void clear(final GL2ES2 gl, final RegionRenderer renderer) {
         synchronized ( dirtySync ) {
             clearImpl0(gl, renderer);
-            position[0] = 0f;
-            position[1] = 0f;
-            position[2] = 0f;
+            position.set(0f, 0f, 0f);
             rotation.setIdentity();
-            rotPivot[0] = 0f;
-            rotPivot[1] = 0f;
-            rotPivot[2] = 0f;
-            scale[0] = 1f;
-            scale[1] = 1f;
-            scale[2] = 1f;
+            rotPivot.set(0f, 0f, 0f);
+            scale.set(1f, 1f, 1f);
             box.reset();
             markShapeDirty();
         }
@@ -164,16 +188,10 @@ public abstract class Shape {
      */
     public final void destroy(final GL2ES2 gl, final RegionRenderer renderer) {
         destroyImpl0(gl, renderer);
-        position[0] = 0f;
-        position[1] = 0f;
-        position[2] = 0f;
+        position.set(0f, 0f, 0f);
         rotation.setIdentity();
-        rotPivot[0] = 0f;
-        rotPivot[1] = 0f;
-        rotPivot[2] = 0f;
-        scale[0] = 1f;
-        scale[1] = 1f;
-        scale[2] = 1f;
+        rotPivot.set(0f, 0f, 0f);
+        scale.set(1f, 1f, 1f);
         box.reset();
         markShapeDirty();
     }
@@ -182,45 +200,53 @@ public abstract class Shape {
 
     /** Move to scaled position. Position ends up in PMVMatrix unmodified. */
     public final void moveTo(final float tx, final float ty, final float tz) {
-        position[0] = tx;
-        position[1] = ty;
-        position[2] = tz;
+        position.set(tx, ty, tz);
+        if( null != onMoveListener ) {
+            onMoveListener.run(this);
+        }
+    }
+
+    /** Move to scaled position. Position ends up in PMVMatrix unmodified. */
+    public final void moveTo(final Vec3f t) {
+        position.set(t);
         if( null != onMoveListener ) {
             onMoveListener.run(this);
         }
-        // System.err.println("Shape.setTranslate: "+tx+"/"+ty+"/"+tz+": "+toString());
     }
 
     /** Move about scaled distance. Position ends up in PMVMatrix unmodified. */
     public final void move(final float dtx, final float dty, final float dtz) {
-        position[0] += dtx;
-        position[1] += dty;
-        position[2] += dtz;
+        position.add(dtx, dty, dtz);
         if( null != onMoveListener ) {
             onMoveListener.run(this);
         }
-        // System.err.println("Shape.translate: "+tx+"/"+ty+"/"+tz+": "+toString());
     }
 
-    /** Returns float[3] position, i.e. scaled translation as set via {@link #moveTo(float, float, float) or {@link #move(float, float, float)}}. */
-    public final float[] getPosition() { return position; }
+    /** Move about scaled distance. Position ends up in PMVMatrix unmodified. */
+    public final void move(final Vec3f dt) {
+        position.add(dt);
+        if( null != onMoveListener ) {
+            onMoveListener.run(this);
+        }
+    }
+
+    /** Returns position, i.e. scaled translation as set via {@link #moveTo(float, float, float) or {@link #move(float, float, float)}}. */
+    public final Vec3f getPosition() { return position; }
 
     /** Returns {@link Quaternion} for rotation. */
     public final Quaternion getRotation() { return rotation; }
-    /** Return float[3] unscaled rotation origin, aka pivot. */
-    public final float[] getRotationPivot() { return rotPivot; }
+    /** Return unscaled rotation origin, aka pivot. */
+    public final Vec3f getRotationPivot() { return rotPivot; }
     /** Set unscaled rotation origin, aka pivot. Usually the {@link #getBounds()} center and should be set while {@link #validateImpl(GLProfile, GL2ES2)}. */
-    public final void setRotationPivot(final float rx, final float ry, final float rz) {
-        rotPivot[0] = rx;
-        rotPivot[1] = ry;
-        rotPivot[2] = rz;
+    public final void setRotationPivot(final float px, final float py, final float pz) {
+        rotPivot.set(px, py, pz);
     }
     /**
      * Set unscaled rotation origin, aka pivot. Usually the {@link #getBounds()} center and should be set while {@link #validateImpl(GLProfile, GL2ES2)}.
-     * @param pivot float[3] rotation origin
+     * @param pivot rotation origin
      */
-    public final void setRotationPivot(final float[/*3*/] pivot) {
-        System.arraycopy(pivot, 0, rotPivot, 0, 3);
+    public final void setRotationPivot(final Vec3f pivot) {
+        rotPivot.set(pivot);
     }
 
     /**
@@ -229,9 +255,7 @@ public abstract class Shape {
      * @see #getScale()
      */
     public final void setScale(final float sx, final float sy, final float sz) {
-        scale[0] = sx;
-        scale[1] = sy;
-        scale[2] = sz;
+        scale.set(sx, sy, sz);
     }
     /**
      * Multiply current scale factor by given scale.
@@ -239,22 +263,14 @@ public abstract class Shape {
      * @see #getScale()
      */
     public final void scale(final float sx, final float sy, final float sz) {
-        scale[0] *= sx;
-        scale[1] *= sy;
-        scale[2] *= sz;
+        scale.scale(sx, sy, sz);
     }
     /**
-     * Returns float[3] scale factors.
+     * Returns scale factors.
      * @see #setScale(float, float, float)
      * @see #scale(float, float, float)
      */
-    public final float[] getScale() { return scale; }
-    /** Returns X-axis scale factor. */
-    public final float getScaleX() { return scale[0]; }
-    /** Returns Y-axis scale factor. */
-    public final float getScaleY() { return scale[1]; }
-    /** Returns Z-axis scale factor. */
-    public final float getScaleZ() { return scale[2]; }
+    public final Vec3f getScale() { return scale; }
 
     /**
      * Marks the shape dirty, causing next {@link #draw(GL2ES2, RegionRenderer, int[]) draw()}
@@ -304,7 +320,7 @@ public abstract class Shape {
      * @see #getBounds()
      */
     public final float getScaledWidth() {
-        return box.getWidth() * getScaleX();
+        return box.getWidth() * getScale().x();
     }
 
     /**
@@ -317,7 +333,7 @@ public abstract class Shape {
      * @see #getBounds()
      */
     public final float getScaledHeight() {
-        return box.getHeight() * getScaleY();
+        return box.getHeight() * getScale().y();
     }
 
     /**
@@ -450,39 +466,39 @@ public abstract class Shape {
      * @see #setScale(float, float, float)
      */
     public void setTransform(final PMVMatrix pmv) {
-        final boolean hasScale = !VectorUtil.isVec3Equal(scale, 0, VectorUtil.VEC3_ONE, 0, FloatUtil.EPSILON);
+        final boolean hasScale = !scale.isEqual(Vec3f.ONE);
         final boolean hasRotate = !rotation.isIdentity();
-        final boolean hasRotPivot = !VectorUtil.isVec3Zero(rotPivot, 0, FloatUtil.EPSILON);
-        final float[] ctr = box.getCenter();
-        final boolean sameScaleRotatePivot = hasScale && hasRotate && ( !hasRotPivot || VectorUtil.isVec3Equal(rotPivot, 0, ctr, 0, FloatUtil.EPSILON) );
+        final boolean hasRotPivot = !rotPivot.isZero();
+        final Vec3f ctr = box.getCenter();
+        final boolean sameScaleRotatePivot = hasScale && hasRotate && ( !hasRotPivot || rotPivot.isEqual(ctr) );
 
-        pmv.glTranslatef(position[0], position[1], position[2]); // translate, scaled
+        pmv.glTranslatef(position.x(), position.y(), position.z()); // translate, scaled
 
         if( sameScaleRotatePivot ) {
             // Scale shape from its center position and rotate around its center
-            pmv.glTranslatef(ctr[0]*scale[0], ctr[1]*scale[1], ctr[2]*scale[2]); // add-back center, scaled
+            pmv.glTranslatef(ctr.x()*scale.x(), ctr.y()*scale.y(), ctr.z()*scale.z()); // add-back center, scaled
             pmv.glRotate(rotation);
-            pmv.glScalef(scale[0], scale[1], scale[2]);
-            pmv.glTranslatef(-ctr[0], -ctr[1], -ctr[2]); // move to center
+            pmv.glScalef(scale.x(), scale.y(), scale.z());
+            pmv.glTranslatef(-ctr.x(), -ctr.y(), -ctr.z()); // move to center
         } else if( hasRotate || hasScale ) {
             if( hasRotate ) {
                 if( hasRotPivot ) {
                     // Rotate shape around its scaled pivot
-                    pmv.glTranslatef(rotPivot[0]*scale[0], rotPivot[1]*scale[1], rotPivot[2]*scale[2]); // pivot back from rot-pivot, scaled
+                    pmv.glTranslatef(rotPivot.x()*scale.x(), rotPivot.y()*scale.y(), rotPivot.z()*scale.z()); // pivot back from rot-pivot, scaled
                     pmv.glRotate(rotation);
-                    pmv.glTranslatef(-rotPivot[0]*scale[0], -rotPivot[1]*scale[1], -rotPivot[2]*scale[2]); // pivot to rot-pivot, scaled
+                    pmv.glTranslatef(-rotPivot.x()*scale.x(), -rotPivot.y()*scale.y(), -rotPivot.z()*scale.z()); // pivot to rot-pivot, scaled
                 } else {
                     // Rotate shape around its scaled center
-                    pmv.glTranslatef(ctr[0]*scale[0], ctr[1]*scale[1], ctr[2]*scale[2]); // pivot back from center-pivot, scaled
+                    pmv.glTranslatef(ctr.x()*scale.x(), ctr.y()*scale.y(), ctr.z()*scale.z()); // pivot back from center-pivot, scaled
                     pmv.glRotate(rotation);
-                    pmv.glTranslatef(-ctr[0]*scale[0], -ctr[1]*scale[1], -ctr[2]*scale[2]); // pivot to center-pivot, scaled
+                    pmv.glTranslatef(-ctr.x()*scale.x(), -ctr.y()*scale.y(), -ctr.z()*scale.z()); // pivot to center-pivot, scaled
                 }
             }
             if( hasScale ) {
                 // Scale shape from its center position
-                pmv.glTranslatef(ctr[0]*scale[0], ctr[1]*scale[1], ctr[2]*scale[2]); // add-back center, scaled
-                pmv.glScalef(scale[0], scale[1], scale[2]);
-                pmv.glTranslatef(-ctr[0], -ctr[1], -ctr[2]); // move to center
+                pmv.glTranslatef(ctr.x()*scale.x(), ctr.y()*scale.y(), ctr.z()*scale.z()); // add-back center, scaled
+                pmv.glScalef(scale.x(), scale.y(), scale.z());
+                pmv.glTranslatef(-ctr.x(), -ctr.y(), -ctr.z()); // move to center
             }
         }
         // TODO: Add alignment features.
@@ -506,12 +522,12 @@ public abstract class Shape {
         // System.err.println("Shape::getSurfaceSize.VP "+viewport[0]+"/"+viewport[1]+" "+viewport[2]+"x"+viewport[3]);
         final float[] winCoordHigh = new float[3];
         final float[] winCoordLow = new float[3];
-        final float[] high = getBounds().getHigh();
-        final float[] low = getBounds().getLow();
+        final Vec3f high = box.getHigh();
+        final Vec3f low = box.getLow();
 
-        if( pmv.gluProject(high[0], high[1], high[2], viewport, 0, winCoordHigh, 0) ) {
+        if( pmv.gluProject(high.x(), high.y(), high.z(), viewport, 0, winCoordHigh, 0) ) {
             // System.err.printf("Shape::surfaceSize.H: shape %d: obj [%f, %f, %f] -> win [%f, %f, %f]%n", getName(), high[0], high[1], high[2], winCoordHigh[0], winCoordHigh[1], winCoordHigh[2]);
-            if( pmv.gluProject(low[0], low[1], low[2], viewport, 0, winCoordLow, 0) ) {
+            if( pmv.gluProject(low.x(), low.y(), low.z(), viewport, 0, winCoordLow, 0) ) {
                 // System.err.printf("Shape::surfaceSize.L: shape %d: obj [%f, %f, %f] -> win [%f, %f, %f]%n", getName(), low[0], low[1], low[2], winCoordLow[0], winCoordLow[1], winCoordLow[2]);
                 surfaceSize[0] = (int)(winCoordHigh[0] - winCoordLow[0]);
                 surfaceSize[1] = (int)(winCoordHigh[1] - winCoordLow[1]);
@@ -611,17 +627,17 @@ public abstract class Shape {
      * </p>
      * @param pmv well formed {@link PMVMatrix}, e.g. could have been setup via {@link Scene#setupMatrix(PMVMatrix) setupMatrix(..)} and {@link #setTransform(PMVMatrix)}.
      * @param viewport the int[4] viewport
-     * @param objPos float[3] object position relative to this shape's center
+     * @param objPos object position relative to this shape's center
      * @param glWinPos int[2] target window position of objPos relative to this shape
      * @return given int[2] {@code glWinPos} for successful gluProject(..) operation, otherwise {@code null}
      * @see #shapeToWinCoord(com.jogamp.graph.ui.Scene.PMVMatrixSetup, int[], float[], PMVMatrix, int[])
      * @see #shapeToWinCoord(Scene, float[], PMVMatrix, int[])
      */
-    public int[/*2*/] shapeToWinCoord(final PMVMatrix pmv, final int[/*4*/] viewport, final float[/*3*/] objPos, final int[/*2*/] glWinPos) {
+    public int[/*2*/] shapeToWinCoord(final PMVMatrix pmv, final int[/*4*/] viewport, final Vec3f objPos, final int[/*2*/] glWinPos) {
         // System.err.println("Shape::objToWinCoordgetSurfaceSize.VP "+viewport[0]+"/"+viewport[1]+" "+viewport[2]+"x"+viewport[3]);
         final float[] winCoord = new float[3];
 
-        if( pmv.gluProject(objPos[0], objPos[1], objPos[2], viewport, 0, winCoord, 0) ) {
+        if( pmv.gluProject(objPos.x(), objPos.y(), objPos.z(), viewport, 0, winCoord, 0) ) {
             // System.err.printf("Shape::objToWinCoord.0: shape %d: obj [%f, %f, %f] -> win [%f, %f, %f]%n", getName(), objPos[0], objPos[1], objPos[2], winCoord[0], winCoord[1], winCoord[2]);
             glWinPos[0] = (int)(winCoord[0]);
             glWinPos[1] = (int)(winCoord[1]);
@@ -639,7 +655,7 @@ public abstract class Shape {
      * </p>
      * @param pmvMatrixSetup {@link Scene.PMVMatrixSetup} to {@link Scene.PMVMatrixSetup#set(PMVMatrix, int, int, int, int) setup} given {@link PMVMatrix} {@code pmv}.
      * @param viewport used viewport for {@link PMVMatrix#gluProject(float, float, float, int[], int, float[], int)}
-     * @param objPos float[3] object position relative to this shape's center
+     * @param objPos object position relative to this shape's center
      * @param pmv a new {@link PMVMatrix} which will {@link Scene.PMVMatrixSetup#set(PMVMatrix, int, int, int, int) be setup},
      *            {@link #setTransform(PMVMatrix) shape-transformed} and can be reused by the caller.
      * @param glWinPos int[2] target window position of objPos relative to this shape
@@ -647,7 +663,7 @@ public abstract class Shape {
      * @see #shapeToWinCoord(PMVMatrix, int[], float[], int[])
      * @see #shapeToWinCoord(Scene, float[], PMVMatrix, int[])
      */
-    public int[/*2*/] shapeToWinCoord(final Scene.PMVMatrixSetup pmvMatrixSetup, final int[/*4*/] viewport, final float[/*3*/] objPos, final PMVMatrix pmv, final int[/*2*/] glWinPos) {
+    public int[/*2*/] shapeToWinCoord(final Scene.PMVMatrixSetup pmvMatrixSetup, final int[/*4*/] viewport, final Vec3f objPos, final PMVMatrix pmv, final int[/*2*/] glWinPos) {
         pmvMatrixSetup.set(pmv, viewport[0], viewport[1], viewport[2], viewport[3]);
         setTransform(pmv);
         return this.shapeToWinCoord(pmv, viewport, objPos, glWinPos);
@@ -660,7 +676,7 @@ public abstract class Shape {
      * including this shape's {@link #setTransform(PMVMatrix)}.
      * </p>
      * @param scene {@link Scene} to retrieve {@link Scene.PMVMatrixSetup} and the viewport.
-     * @param objPos float[3] object position relative to this shape's center
+     * @param objPos object position relative to this shape's center
      * @param pmv a new {@link PMVMatrix} which will {@link Scene.PMVMatrixSetup#set(PMVMatrix, int, int, int, int) be setup},
      *            {@link #setTransform(PMVMatrix) shape-transformed} and can be reused by the caller.
      * @param glWinPos int[2] target window position of objPos relative to this shape
@@ -668,7 +684,7 @@ public abstract class Shape {
      * @see #shapeToWinCoord(PMVMatrix, int[], float[], int[])
      * @see #shapeToWinCoord(com.jogamp.graph.ui.Scene.PMVMatrixSetup, int[], float[], PMVMatrix, int[])
      */
-    public int[/*2*/] shapeToWinCoord(final Scene scene, final float[/*3*/] objPos, final PMVMatrix pmv, final int[/*2*/] glWinPos) {
+    public int[/*2*/] shapeToWinCoord(final Scene scene, final Vec3f objPos, final PMVMatrix pmv, final int[/*2*/] glWinPos) {
         return this.shapeToWinCoord(scene.getPMVMatrixSetup(), scene.getViewport(), objPos, pmv, glWinPos);
     }
 
@@ -683,19 +699,21 @@ public abstract class Shape {
      * @param viewport the int[4] viewport
      * @param glWinX in GL window coordinates, origin bottom-left
      * @param glWinY in GL window coordinates, origin bottom-left
-     * @param objPos float[3] target object position of glWinX/glWinY relative to this shape
-     * @return given float[3] {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
+     * @param objPos target object position of glWinX/glWinY relative to this shape
+     * @return given {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
      * @see #winToShapeCoord(com.jogamp.graph.ui.Scene.PMVMatrixSetup, int[], int, int, PMVMatrix, float[])
      * @see #winToShapeCoord(Scene, int, int, PMVMatrix, float[])
      */
-    public float[/*3*/] winToShapeCoord(final PMVMatrix pmv, final int[/*4*/] viewport, final int glWinX, final int glWinY, final float[/*3*/] objPos) {
-        final float[] ctr = getBounds().getCenter();
+    public Vec3f winToShapeCoord(final PMVMatrix pmv, final int[/*4*/] viewport, final int glWinX, final int glWinY, final Vec3f objPos) {
+        final Vec3f ctr = box.getCenter();
         final float[] tmp = new float[3];
 
-        if( pmv.gluProject(ctr[0], ctr[1], ctr[2], viewport, 0, tmp, 0) ) {
+        if( pmv.gluProject(ctr.x(), ctr.y(), ctr.z(), viewport, 0, tmp, 0) ) {
             // System.err.printf("Shape::winToObjCoord.0: shape %d: obj [%15.10ff, %15.10ff, %15.10ff] -> win [%d / %d -> %7.2ff, %7.2ff, %7.2ff, diff %7.2ff x %7.2ff]%n", getName(), ctr[0], ctr[1], ctr[2], glWinX, glWinY, tmp[0], tmp[1], tmp[2], glWinX-tmp[0], glWinY-tmp[1]);
-            if( pmv.gluUnProject(glWinX, glWinY, tmp[2], viewport, 0, objPos, 0) ) {
+            final float winZ = tmp[2];
+            if( pmv.gluUnProject(glWinX, glWinY, winZ, viewport, 0, objPos.get(tmp), 0) ) {
                 // System.err.printf("Shape::winToObjCoord.X: shape %d: win [%d, %d, %7.2ff] -> obj [%15.10ff, %15.10ff, %15.10ff]%n", getName(), glWinX, glWinY, tmp[2], objPos[0], objPos[1], objPos[2]);
+                objPos.set(tmp);
                 return objPos;
             }
         }
@@ -714,12 +732,12 @@ public abstract class Shape {
      * @param glWinY in GL window coordinates, origin bottom-left
      * @param pmv a new {@link PMVMatrix} which will {@link Scene.PMVMatrixSetup#set(PMVMatrix, int, int, int, int) be setup},
      *            {@link #setTransform(PMVMatrix) shape-transformed} and can be reused by the caller.
-     * @param objPos float[3] target object position of glWinX/glWinY relative to this shape
-     * @return given float[3] {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
+     * @param objPos target object position of glWinX/glWinY relative to this shape
+     * @return given {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
      * @see #winToShapeCoord(PMVMatrix, int[], int, int, float[])
      * @see #winToShapeCoord(Scene, int, int, PMVMatrix, float[])
      */
-    public float[/*3*/] winToShapeCoord(final Scene.PMVMatrixSetup pmvMatrixSetup, final int[/*4*/] viewport, final int glWinX, final int glWinY, final PMVMatrix pmv, final float[/*3*/] objPos) {
+    public Vec3f winToShapeCoord(final Scene.PMVMatrixSetup pmvMatrixSetup, final int[/*4*/] viewport, final int glWinX, final int glWinY, final PMVMatrix pmv, final Vec3f objPos) {
         pmvMatrixSetup.set(pmv, viewport[0], viewport[1], viewport[2], viewport[3]);
         setTransform(pmv);
         return this.winToShapeCoord(pmv, viewport, glWinX, glWinY, objPos);
@@ -736,12 +754,12 @@ public abstract class Shape {
      * @param glWinY in GL window coordinates, origin bottom-left
      * @param pmv a new {@link PMVMatrix} which will {@link Scene.PMVMatrixSetup#set(PMVMatrix, int, int, int, int) be setup},
      *            {@link #setTransform(PMVMatrix) shape-transformed} and can be reused by the caller.
-     * @param objPos float[3] target object position of glWinX/glWinY relative to this shape
-     * @return given float[3] {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
+     * @param objPos target object position of glWinX/glWinY relative to this shape
+     * @return given {@code objPos} for successful gluProject(..) and gluUnProject(..) operation, otherwise {@code null}
      * @see #winToShapeCoord(PMVMatrix, int[], int, int, float[])
      * @see #winToShapeCoord(com.jogamp.graph.ui.Scene.PMVMatrixSetup, int[], int, int, PMVMatrix, float[])
      */
-    public float[/*3*/] winToShapeCoord(final Scene scene, final int glWinX, final int glWinY, final PMVMatrix pmv, final float[/*3*/] objPos) {
+    public Vec3f winToShapeCoord(final Scene scene, final int glWinX, final int glWinY, final PMVMatrix pmv, final Vec3f objPos) {
         return this.winToShapeCoord(scene.getPMVMatrixSetup(), scene.getViewport(), glWinX, glWinY, pmv, objPos);
     }
 
@@ -808,14 +826,14 @@ public abstract class Shape {
 
     public String getSubString() {
         final String pivotS;
-        if( !VectorUtil.isVec3Zero(rotPivot, 0, FloatUtil.EPSILON) ) {
-            pivotS = "pivot["+rotPivot[0]+", "+rotPivot[1]+", "+rotPivot[2]+"], ";
+        if( !rotPivot.isZero() ) {
+            pivotS = "pivot["+rotPivot+"], ";
         } else {
             pivotS = "";
         }
         final String scaleS;
-        if( !VectorUtil.isVec3Equal(scale, 0, VectorUtil.VEC3_ONE, 0, FloatUtil.EPSILON) ) {
-            scaleS = "scale["+scale[0]+", "+scale[1]+", "+scale[2]+"], ";
+        if( !scale.isEqual( Vec3f.ONE ) ) {
+            scaleS = "scale["+scale+"], ";
         } else {
             scaleS = "scale 1, ";
         }
@@ -825,7 +843,7 @@ public abstract class Shape {
         } else {
             rotateS = "";
         }
-        return "enabled "+enabled+", toggle[able "+toggleable+", state "+toggle+"], pos["+position[0]+", "+position[1]+", "+position[2]+
+        return "enabled "+enabled+", toggle[able "+toggleable+", state "+toggle+"], pos["+position+
                 "], "+pivotS+scaleS+rotateS+
                 "box "+box;
     }
@@ -842,6 +860,11 @@ public abstract class Shape {
         return this.down;
     }
 
+    /**
+     *
+     * @param toggleable
+     * @see #isInteractive()
+     */
     public void setToggleable(final boolean toggleable) {
         this.toggleable = toggleable;
     }
@@ -849,6 +872,7 @@ public abstract class Shape {
     /**
      * Returns true if this shape is toggable,
      * i.e. rendered w/ {@link #setToggleOnColorMod(float, float, float, float)} or {@link #setToggleOffColorMod(float, float, float, float)}.
+     * @see #isInteractive()
      */
     public boolean isToggleable() {
         return toggleable;
@@ -866,15 +890,36 @@ public abstract class Shape {
     public boolean isToggleOn() { return toggle; }
 
     /**
+     * Set whether this shape is interactive,
+     * i.e. any user interaction like
+     * - {@link #isToggleable()}
+     * - {@link #isDraggable()}
+     * - {@link #isResizable()}
+     * but excluding programmatic changes.
+     * @param v new value for {@link #isInteractive()}
+     */
+    public void setInteractive(final boolean v) { interactive = v; }
+    /**
+     * Returns if this shape allows user interaction, see {@link #setInteractive(boolean)}
+     * @see #setInteractive(boolean)
+     */
+    public boolean isInteractive() { return interactive; }
+
+    /**
      * Set whether this shape is draggable,
      * i.e. translated by 1-pointer-click and drag.
      * <p>
      * Default draggable is true.
      * </p>
+     * @see #isInteractive()
      */
     public void setDraggable(final boolean draggable) {
         this.draggable = draggable;
     }
+    /**
+     * Returns if this shape is draggable, a user interaction.
+     * @see #isInteractive()
+     */
     public boolean isDraggable() {
         return draggable;
     }
@@ -885,10 +930,15 @@ public abstract class Shape {
      * <p>
      * Default resizable is true.
      * </p>
+     * @see #isInteractive()
      */
     public void setResizable(final boolean resizable) {
         this.resizable = resizable;
     }
+    /**
+     * Returns if this shape is resiable, a user interaction.
+     * @see #isInteractive()
+     */
     public boolean isResizable() {
         return resizable;
     }
@@ -938,11 +988,11 @@ public abstract class Shape {
         /** The associated {@link Shape} for this event */
         public final Shape shape;
         /** The relative object coordinate of glWinX/glWinY to the associated {@link Shape}. */
-        public final float[] objPos;
+        public final Vec3f objPos;
         /** The GL window coordinates, origin bottom-left */
         public final int[] winPos;
         /** The drag delta of the relative object coordinate of glWinX/glWinY to the associated {@link Shape}. */
-        public final float[] objDrag = { 0f, 0f };
+        public final Vec2f objDrag = new Vec2f();
         /** The drag delta of GL window coordinates, origin bottom-left */
         public final int[] winDrag = { 0, 0 };
 
@@ -953,7 +1003,7 @@ public abstract class Shape {
          * @param shape associated shape
          * @param objPos relative object coordinate of glWinX/glWinY to the associated shape.
          */
-        EventInfo(final int glWinX, final int glWinY, final Shape shape, final float[] objPos) {
+        EventInfo(final int glWinX, final int glWinY, final Shape shape, final Vec3f objPos) {
             this.winPos = new int[] { glWinX, glWinY };
             this.shape = shape;
             this.objPos = objPos;
@@ -961,14 +1011,14 @@ public abstract class Shape {
 
         @Override
         public String toString() {
-            return "EventDetails[winPos ["+winPos[0]+", "+winPos[1]+"], objPos ["+objPos[0]+", "+objPos[1]+", "+objPos[2]+"], "+shape+"]";
+            return "EventDetails[winPos ["+winPos[0]+", "+winPos[1]+"], objPos ["+objPos+"], "+shape+"]";
         }
     }
 
     private boolean dragFirst = false;
-    private final float[] objDraggedFirst = { 0f, 0f }; // b/c its relative to Shape and we stick to it
+    private final Vec2f objDraggedFirst = new Vec2f(); // b/c its relative to Shape and we stick to it
     private final int[] winDraggedLast = { 0, 0 }; // b/c its absolute window pos
-    private boolean inDrag = false;
+    private boolean inMove = false;
     private int inResize = 0; // 1 br, 2 bl
     private static final float resize_sxy_min = 1f/200f; // 1/2% - TODO: Maybe customizable?
     private static final float resize_section = 1f/5f; // resize action in a corner
@@ -980,7 +1030,7 @@ public abstract class Shape {
      * @param glWinY in GL window coordinates, origin bottom-left
      * @param objPos object position of mouse event relative to this shape
      */
-    /* pp */ final void dispatchMouseEvent(final MouseEvent e, final int glWinX, final int glWinY, final float[] objPos) {
+    /* pp */ final void dispatchMouseEvent(final MouseEvent e, final int glWinX, final int glWinY, final Vec3f objPos) {
         final Shape.EventInfo shapeEvent = new EventInfo(glWinX, glWinY, this, objPos);
 
         final short eventType = e.getEventType();
@@ -996,7 +1046,7 @@ public abstract class Shape {
                 case MouseEvent.EVENT_MOUSE_RELEASED:
                     // Release active shape: last pointer has been lifted!
                     setPressed(false);
-                    inDrag = false;
+                    inMove = false;
                     inResize = 0;
                     break;
             }
@@ -1005,21 +1055,22 @@ public abstract class Shape {
             case MouseEvent.EVENT_MOUSE_DRAGGED: {
                 // 1 pointer drag and potential drag-resize
                 if(dragFirst) {
-                    objDraggedFirst[0] = objPos[0];
-                    objDraggedFirst[1] = objPos[1];
+                    objDraggedFirst.set(objPos);
                     winDraggedLast[0] = glWinX;
                     winDraggedLast[1] = glWinY;
                     dragFirst=false;
 
-                    final float ix = objPos[0];
-                    final float iy = objPos[1];
+                    final float ix = objPos.x();
+                    final float iy = objPos.y();
                     final float minx_br = box.getMaxX() - box.getWidth() * resize_section;
                     final float miny_br = box.getMinY();
                     final float maxx_br = box.getMaxX();
                     final float maxy_br = box.getMinY() + box.getHeight() * resize_section;
                     if( minx_br <= ix && ix <= maxx_br &&
                         miny_br <= iy && iy <= maxy_br ) {
-                        inResize = 1; // bottom-right
+                        if( interactive && resizable ) {
+                            inResize = 1; // bottom-right
+                        }
                     } else {
                         final float minx_bl = box.getMinX();
                         final float miny_bl = box.getMinY();
@@ -1027,57 +1078,59 @@ public abstract class Shape {
                         final float maxy_bl = box.getMinY() + box.getHeight() * resize_section;
                         if( minx_bl <= ix && ix <= maxx_bl &&
                             miny_bl <= iy && iy <= maxy_bl ) {
-                            inResize = 2; // bottom-left
+                            if( interactive && resizable ) {
+                                inResize = 2; // bottom-left
+                            }
                         } else {
-                            inDrag = true;
+                            inMove = interactive && draggable;
                         }
                     }
                     if( DEBUG ) {
-                        System.err.printf("DragFirst: drag %b, resize %d, obj[%.4f, %.4f, %.4f], drag +[%.4f, %.4f]%n",
-                                inDrag, inResize, objPos[0], objPos[1], objPos[2], shapeEvent.objDrag[0], shapeEvent.objDrag[1]);
+                        System.err.printf("DragFirst: drag %b, resize %d, obj[%s], drag +[%s]%n",
+                                inMove, inResize, objPos, shapeEvent.objDrag);
                         System.err.printf("DragFirst: %s%n", this);
                     }
                     return;
                 }
-                shapeEvent.objDrag[0] = objPos[0] - objDraggedFirst[0];
-                shapeEvent.objDrag[1] = objPos[1] - objDraggedFirst[1];
+                shapeEvent.objDrag.set( objPos.x() - objDraggedFirst.x(),
+                                        objPos.y() - objDraggedFirst.y() );
                 shapeEvent.winDrag[0] = glWinX - winDraggedLast[0];
                 shapeEvent.winDrag[1] = glWinY - winDraggedLast[1];
                 winDraggedLast[0] = glWinX;
                 winDraggedLast[1] = glWinY;
                 if( 1 == e.getPointerCount() ) {
-                    final float sdx = shapeEvent.objDrag[0] * scale[0]; // apply scale, since operation
-                    final float sdy = shapeEvent.objDrag[1] * scale[1]; // is from a scaled-model-viewpoint
-                    if( 0 != inResize && resizable ) {
+                    final float sdx = shapeEvent.objDrag.x() * scale.x(); // apply scale, since operation
+                    final float sdy = shapeEvent.objDrag.y() * scale.y(); // is from a scaled-model-viewpoint
+                    if( 0 != inResize ) {
                         final float bw = box.getWidth();
                         final float bh = box.getHeight();
                         final float sx;
                         if( 1 == inResize ) {
-                            sx = scale[0] + sdx/bw; // bottom-right
+                            sx = scale.x() + sdx/bw; // bottom-right
                         } else {
-                            sx = scale[0] - sdx/bw; // bottom-left
+                            sx = scale.x() - sdx/bw; // bottom-left
                         }
-                        final float sy = scale[1] - sdy/bh;
+                        final float sy = scale.y() - sdy/bh;
                         if( resize_sxy_min <= sx && resize_sxy_min <= sy ) { // avoid scale flip
                             if( DEBUG ) {
-                                System.err.printf("DragZoom: resize %d, win[%4d, %4d], obj[%.4f, %.4f, %.4f], dxy +[%.4f, %.4f], sdxy +[%.4f, %.4f], scale [%.4f, %.4f] -> [%.4f, %.4f]%n",
-                                        inResize, glWinX, glWinY, objPos[0], objPos[1], objPos[2],
-                                        shapeEvent.objDrag[0], shapeEvent.objDrag[1], sdx, sdy,
-                                        scale[0], scale[1], sx, sy);
+                                System.err.printf("DragZoom: resize %d, win[%4d, %4d], obj[%s], dxy +[%s], sdxy +[%.4f, %.4f], scale [%s] -> [%.4f, %.4f]%n",
+                                        inResize, glWinX, glWinY, objPos,
+                                        shapeEvent.objDrag, sdx, sdy,
+                                        scale, sx, sy);
                             }
                             if( 1 == inResize ) {
                                 move(   0, sdy, 0f); // bottom-right, sticky left- and top-edge
                             } else {
                                 move( sdx, sdy, 0f); // bottom-left, sticky right- and top-edge
                             }
-                            setScale(sx, sy, scale[2]);
+                            setScale(sx, sy, scale.z());
                         }
                         return; // FIXME: pass through event? Issue zoom event?
-                    } else if( inDrag && draggable ) {
+                    } else if( inMove ) {
                         if( DEBUG ) {
-                            System.err.printf("DragMove: win[%4d, %4d] +[%2d, %2d], obj[%.4f, %.4f, %.4f] +[%.4f, %.4f]%n",
+                            System.err.printf("DragMove: win[%4d, %4d] +[%2d, %2d], obj[%s] +[%s]%n",
                                     glWinX, glWinY, shapeEvent.winDrag[0], shapeEvent.winDrag[1],
-                                    objPos[0], objPos[1], objPos[2], shapeEvent.objDrag[0], shapeEvent.objDrag[1]);
+                                    objPos, shapeEvent.objDrag);
                         }
                         move( sdx, sdy, 0f);
                         // FIXME: Pass through event? Issue move event?
@@ -1129,32 +1182,30 @@ public abstract class Shape {
      * @param viewport the viewport
      * @param objPos object position of mouse event relative to this shape
      */
-    /* pp */ final void dispatchGestureEvent(final GestureEvent e, final int glWinX, final int glWinY, final PMVMatrix pmv, final int[] viewport, final float[] objPos) {
-        if( resizable && e instanceof PinchToZoomGesture.ZoomEvent ) {
+    /* pp */ final void dispatchGestureEvent(final GestureEvent e, final int glWinX, final int glWinY, final PMVMatrix pmv, final int[] viewport, final Vec3f objPos) {
+        if( interactive && resizable && e instanceof PinchToZoomGesture.ZoomEvent ) {
             final PinchToZoomGesture.ZoomEvent ze = (PinchToZoomGesture.ZoomEvent) e;
             final float pixels = ze.getDelta() * ze.getScale(); //
             final int winX2 = glWinX + Math.round(pixels);
-            final float[] objPos2 = winToShapeCoord(pmv, viewport, winX2, glWinY, new float[3]);
+            final Vec3f objPos2 = winToShapeCoord(pmv, viewport, winX2, glWinY, new Vec3f());
             if( null == objPos2 ) {
                 return;
             }
-            final float dx = objPos2[0];
-            final float dy = objPos2[1];
-            final float sx = scale[0] + ( dx/box.getWidth() ); // bottom-right
-            final float sy = scale[1] + ( dy/box.getHeight() );
+            final float dx = objPos2.x();
+            final float dy = objPos2.y();
+            final float sx = scale.x() + ( dx/box.getWidth() ); // bottom-right
+            final float sy = scale.y() + ( dy/box.getHeight() );
             if( DEBUG ) {
-                System.err.printf("DragZoom: resize %b, obj %4d/%4d, %.3f/%.3f/%.3f %.3f/%.3f/%.3f + %.3f/%.3f -> %.3f/%.3f%n",
-                        inResize, glWinX, glWinY, objPos[0], objPos[1], objPos[2], position[0], position[1], position[2],
-                        dx, dy, sx, sy);
+                System.err.printf("DragZoom: resize %b, win %4d/%4d, obj %s, %s + %.3f/%.3f -> %.3f/%.3f%n",
+                        inResize, glWinX, glWinY, objPos, position, dx, dy, sx, sy);
             }
             if( resize_sxy_min <= sx && resize_sxy_min <= sy ) { // avoid scale flip
                 if( DEBUG ) {
-                    System.err.printf("PinchZoom: pixels %f, obj %4d/%4d, %.3f/%.3f/%.3f %.3f/%.3f/%.3f + %.3f/%.3f -> %.3f/%.3f%n",
-                            pixels, glWinX, glWinY, objPos[0], objPos[1], objPos[2], position[0], position[1], position[2],
-                            dx, dy, sx, sy);
+                    System.err.printf("PinchZoom: pixels %f, win %4d/%4d, obj %s, %s + %.3f/%.3f -> %.3f/%.3f%n",
+                            pixels, glWinX, glWinY, objPos, position, dx, dy, sx, sy);
                 }
                 // move(dx, dy, 0f);
-                setScale(sx, sy, scale[2]);
+                setScale(sx, sy, scale.z());
             }
             return; // FIXME: pass through event? Issue zoom event?
         }
@@ -1189,8 +1240,8 @@ public abstract class Shape {
     public static Comparator<Shape> ZAscendingComparator = new Comparator<Shape>() {
         @Override
         public int compare(final Shape s1, final Shape s2) {
-            final float s1Z = s1.getBounds().getMinZ()+s1.getPosition()[2];
-            final float s2Z = s2.getBounds().getMinZ()+s2.getPosition()[2];
+            final float s1Z = s1.getBounds().getMinZ()+s1.getPosition().z();
+            final float s2Z = s2.getBounds().getMinZ()+s2.getPosition().z();
             if( FloatUtil.isEqual(s1Z, s2Z, FloatUtil.EPSILON) ) {
                 return 0;
             } else if( s1Z < s2Z ){
diff --git a/src/graphui/classes/com/jogamp/graph/ui/layout/GridLayout.java b/src/graphui/classes/com/jogamp/graph/ui/layout/GridLayout.java
new file mode 100644
index 000000000..bd2fd2d76
--- /dev/null
+++ b/src/graphui/classes/com/jogamp/graph/ui/layout/GridLayout.java
@@ -0,0 +1,69 @@
+/**
+ * Copyright 2010-2023 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 com.jogamp.graph.ui.layout;
+
+import com.jogamp.graph.ui.Group;
+import com.jogamp.graph.ui.Shape;
+import com.jogamp.graph.ui.Group.Layout;
+
+public class GridLayout implements Group.Layout {
+    private final int columns;
+    private final float padX, padY;
+
+    /**
+     *
+     * @param columns [1..inf)
+     * @param padX
+     * @param padY
+     */
+    public GridLayout(final int columns, final float padX, final float padY) {
+        this.columns = Math.max(1, columns);
+        this.padX = padX;
+        this.padY = padY;
+    }
+
+    @Override
+    public void layout(final Group g) {
+        int col = 0;
+        float x=0;
+        float y=0;
+        for(final Shape s : g.getShapes()) {
+            s.moveTo(x, y, 0);
+            if( col + 1 == columns ) {
+                col = 0;
+                // row++;
+                x  = 0;
+                y -= padY;
+            } else {
+                col++;
+                x += padX;
+            }
+        }
+    }
+}
+
diff --git a/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java b/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
index ca726e30f..e8b0be863 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/shapes/Button.java
@@ -35,6 +35,8 @@ import com.jogamp.graph.curve.opengl.RegionRenderer;
 import com.jogamp.graph.font.Font;
 import com.jogamp.graph.geom.plane.AffineTransform;
 import com.jogamp.graph.ui.GraphShape;
+import com.jogamp.opengl.math.Vec2f;
+import com.jogamp.opengl.math.Vec3f;
 import com.jogamp.opengl.math.geom.AABBox;
 
 import jogamp.graph.ui.shapes.Label0;
@@ -111,11 +113,11 @@ public class Button extends RoundButton {
         final float lScale = lsx < lsy ? lsx : lsy;
 
         // Setting left-corner transform using text-box in font em-size [0..1]
-        final AABBox lbox1_s = new AABBox(lbox0_em).scale2(lScale, new float[3]);
+        final AABBox lbox1_s = new AABBox(lbox0_em).scale2(lScale);
         // Center text .. (share same center w/ button)
-        final float[] lctr = lbox1_s.getCenter();
-        final float[] ctr = box.getCenter();
-        final float[] ltxy = new float[] { ctr[0] - lctr[0], ctr[1] - lctr[1] };
+        final Vec3f lctr = lbox1_s.getCenter();
+        final Vec3f ctr = box.getCenter();
+        final Vec2f ltxy = new Vec2f(ctr.x() - lctr.x(), ctr.y() - lctr.y() );
 
         if( DEBUG_DRAW ) {
             System.err.println("Button: dim "+width+" x "+height+", spacing "+spacingX+", "+spacingY);
@@ -124,7 +126,7 @@ public class Button extends RoundButton {
             System.err.println("Button: text_em "+lbox0_em+" em, "+label.getText());
             System.err.println("Button: lscale "+lsx+" x "+lsy+" -> "+lScale);
             System.err.printf ("Button: text_s  %s%n", lbox1_s);
-            System.err.printf ("Button: ltxy %f / %f, %f / %f%n", ltxy[0], ltxy[1], ltxy[0] * lScale, ltxy[1] * lScale);
+            System.err.printf ("Button: ltxy %s, %f / %f%n", ltxy, ltxy.x() * lScale, ltxy.y() * lScale);
         }
 
         final AABBox lbox2 = label.addShapeToRegion(lScale, region, ltxy, tempT1, tempT2, tempT3);
diff --git a/src/graphui/classes/com/jogamp/graph/ui/shapes/Label.java b/src/graphui/classes/com/jogamp/graph/ui/shapes/Label.java
index e7d89ade4..50b53e6f5 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/shapes/Label.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/shapes/Label.java
@@ -166,7 +166,7 @@ public class Label extends GraphShape {
 
     /** Returns {@link Font#getLineHeight()} * {@link #getFontScale()} * {@link #getScaleY()}. */
     public float getScaledLineHeight() {
-        return getScaleY() * fontScale * font.getLineHeight();
+        return getScale().y() * fontScale * font.getLineHeight();
     }
 
     /**
diff --git a/src/graphui/classes/jogamp/graph/ui/TreeTool.java b/src/graphui/classes/jogamp/graph/ui/TreeTool.java
new file mode 100644
index 000000000..ff893ab56
--- /dev/null
+++ b/src/graphui/classes/jogamp/graph/ui/TreeTool.java
@@ -0,0 +1,159 @@
+/**
+ * Copyright 2023 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 jogamp.graph.ui;
+
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+import com.jogamp.graph.ui.Container;
+import com.jogamp.graph.ui.Scene;
+import com.jogamp.graph.ui.Shape;
+import com.jogamp.graph.ui.Shape.Visitor1;
+import com.jogamp.graph.ui.Shape.Visitor2;
+import com.jogamp.opengl.util.PMVMatrix;
+
+/** Generic static {@link Shape} tree traversal tools, utilized by {@link Scene} and {@link Container} implementations. */
+public class TreeTool {
+
+    /**
+     * Traverses through the graph up until {@code shape} and apply {@code action} on it.
+     * @param pmv
+     * @param shape
+     * @param action
+     * @return true to signal operation complete, i.e. {@code shape} found, otherwise false
+     */
+    public static boolean forOne(final List<Shape> shapes, final PMVMatrix pmv, final Shape shape, final Runnable action) {
+        for(int i=shapes.size()-1; i>=0; i--) {
+            final Shape s = shapes.get(i);
+            if( s instanceof Container ) {
+                final Container c = (Container)s;
+                if( !c.contains(shape) ) { // fast-path: skip container
+                    continue;
+                }
+                pmv.glPushMatrix();
+                s.setTransform(pmv);
+                final boolean res = c.forOne(pmv, shape, action);
+                pmv.glPopMatrix();
+                if( !res ) { throw new InternalError("Not found "+shape+" in "+c+", but contained"); }
+                return true;
+            } else {
+                if( s.equals(shape) ) {
+                    pmv.glPushMatrix();
+                    s.setTransform(pmv);
+                    action.run();
+                    pmv.glPopMatrix();
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor1#visit(Shape)} for each, stop if it returns true.
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor1#visit(Shape)} returned true, otherwise false
+     */
+    public static boolean forAll(final List<Shape> shapes, final Visitor1 v) {
+        for(int i=shapes.size()-1; i>=0; i--) {
+            final Shape s = shapes.get(i);
+            boolean res;
+            if( s instanceof Container ) {
+                final Container c = (Container)s;
+                res = c.forAll(v);
+            } else {
+                res = v.visit(s);
+            }
+            if( res ) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor2#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    public static boolean forAll(final List<Shape> shapes, final PMVMatrix pmv, final Visitor2 v) {
+        for(int i=shapes.size()-1; i>=0; i--) {
+            final Shape s = shapes.get(i);
+            pmv.glPushMatrix();
+            s.setTransform(pmv);
+            boolean res;
+            if( s instanceof Container ) {
+                final Container c = (Container)s;
+                res = c.forAll(pmv, v);
+            } else {
+                res = v.visit(s, pmv);
+            }
+            pmv.glPopMatrix();
+            if( res ) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Traverses through the graph and apply {@link Visitor#visit(Shape, PMVMatrix)} for each, stop if it returns true.
+     *
+     * Each {@link Container} level is sorted using {@code sortComp}
+     * @param sortComp
+     * @param pmv
+     * @param v
+     * @return true to signal operation complete and to stop traversal, i.e. {@link Visitor2#visit(Shape, PMVMatrix)} returned true, otherwise false
+     */
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    public static boolean forSortedAll(final Comparator<Shape> sortComp, final List<Shape> shapes, final PMVMatrix pmv, final Visitor2 v) {
+        final Object[] shapesS = shapes.toArray();
+        Arrays.sort(shapesS, (Comparator)sortComp);
+
+        for(int i=shapesS.length-1; i>=0; i--) {
+            final Shape s = (Shape)shapesS[i];
+            pmv.glPushMatrix();
+            s.setTransform(pmv);
+            boolean res;
+            if( s instanceof Container ) {
+                final Container c = (Container)s;
+                res = c.forAll(pmv, v);
+            } else {
+                res = v.visit(s, pmv);
+            }
+            pmv.glPopMatrix();
+            if( res ) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+}
diff --git a/src/graphui/classes/jogamp/graph/ui/shapes/Label0.java b/src/graphui/classes/jogamp/graph/ui/shapes/Label0.java
index fe5f7f8e5..a091a89ed 100644
--- a/src/graphui/classes/jogamp/graph/ui/shapes/Label0.java
+++ b/src/graphui/classes/jogamp/graph/ui/shapes/Label0.java
@@ -31,6 +31,7 @@ import com.jogamp.graph.curve.Region;
 import com.jogamp.graph.curve.opengl.TextRegionUtil;
 import com.jogamp.graph.font.Font;
 import com.jogamp.graph.geom.plane.AffineTransform;
+import com.jogamp.opengl.math.Vec2f;
 import com.jogamp.opengl.math.geom.AABBox;
 
 public class Label0 {
@@ -65,10 +66,10 @@ public class Label0 {
         this.font = font;
     }
 
-    public final AABBox addShapeToRegion(final float scale, final Region region, final float[] txy,
+    public final AABBox addShapeToRegion(final float scale, final Region region, final Vec2f txy,
                                          final AffineTransform tmp1, final AffineTransform tmp2, final AffineTransform tmp3)
     {
-        tmp1.setToTranslation(txy[0], txy[1]);
+        tmp1.setToTranslation(txy.x(), txy.y());
         tmp1.scale(scale, scale, tmp2);
         return TextRegionUtil.addStringToRegion(region, font, tmp1, text, rgbaColor, tmp2, tmp3);
     }