wlu: fixed a potential concurrent access issue.
diff --git a/1.5/plugins/org.eclipse.epf.library.edit/src/org/eclipse/epf/library/edit/TransientGroupItemProvider.java b/1.5/plugins/org.eclipse.epf.library.edit/src/org/eclipse/epf/library/edit/TransientGroupItemProvider.java
index 17c3dcd..aee853b 100644
--- a/1.5/plugins/org.eclipse.epf.library.edit/src/org/eclipse/epf/library/edit/TransientGroupItemProvider.java
+++ b/1.5/plugins/org.eclipse.epf.library.edit/src/org/eclipse/epf/library/edit/TransientGroupItemProvider.java
@@ -230,6 +230,7 @@
 			EStructuralFeature feature = (EStructuralFeature) i.next();
 			if (feature.isMany()) {
 				List children = (List) eObject.eGet(feature);
+				children = new ArrayList(children);
 				int index = 0;
 				for (Iterator ci = children.iterator(); ci.hasNext(); index++) {
 					Object child = ci.next();