2 files changed, 4 insertions, 4 deletions
diff --git a/src/graphui/classes/com/jogamp/graph/ui/Group.java b/src/graphui/classes/com/jogamp/graph/ui/Group.java
index 80783d94c..6e181a0a1 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/Group.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/Group.java
@@ -27,11 +27,11 @@
  */
 package com.jogamp.graph.ui;
 
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import com.jogamp.graph.curve.Region;
 import com.jogamp.graph.curve.opengl.RegionRenderer;
@@ -71,7 +71,7 @@ public class Group extends Shape implements Container {
         void layout(final Group g, final AABBox box, final PMVMatrix pmv);
     }
 
-    private final List<Shape> shapes = new ArrayList<Shape>();
+    private final List<Shape> shapes = new CopyOnWriteArrayList<Shape>();
     private Layout layouter;
     private Rectangle border = null;
 
diff --git a/src/graphui/classes/com/jogamp/graph/ui/Scene.java b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
index 5100aabf7..6abbc7f08 100644
--- a/src/graphui/classes/com/jogamp/graph/ui/Scene.java
+++ b/src/graphui/classes/com/jogamp/graph/ui/Scene.java
@@ -29,12 +29,12 @@ package com.jogamp.graph.ui;
 
 import java.io.File;
 import java.nio.ByteBuffer;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import com.jogamp.opengl.FPSCounter;
 import com.jogamp.opengl.GL;
@@ -109,7 +109,7 @@ public final class Scene implements Container, GLEventListener {
     @SuppressWarnings("unused")
     private static final boolean DEBUG = false;
 
-    private final List<Shape> shapes = new ArrayList<Shape>();
+    private final List<Shape> shapes = new CopyOnWriteArrayList<Shape>();
     private float dbgBorderThickness = 0f;
     private boolean doFrustumCulling = false;