diff --git a/org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gef/part/menu/MenuObjectEditPart.java b/org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gef/part/menu/MenuObjectEditPart.java
index fe992770d..ee68e0465 100644
--- a/org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gef/part/menu/MenuObjectEditPart.java
+++ b/org.eclipse.wb.core/src/org/eclipse/wb/internal/core/gef/part/menu/MenuObjectEditPart.java
@@ -205,7 +205,7 @@ public EditPart getTargetEditPart(Request request) {
 				public void run() {
 					try {
 						MenuObjectInfoUtils.m_selectingObject = m_object;
-						for (EditPart editPart : getViewer().getEditPartRegistry().values()) {
+						for (EditPart editPart : List.copyOf(getViewer().getEditPartRegistry().values())) {
 							if (editPart instanceof MenuObjectEditPart) {
 								editPart.refresh();
 							}