guard for some corner case

refs 2553

org.fortiss.tooling.kernel.ui/trunk/src/org/fortiss/tooling/kernel/ui/internal/views/ConstraintMenu.java

@@ -49,7 +49,7 @@ import org.fortiss.tooling.kernel.ui.service.IModelElementHandlerService;
  * @author hoelzl
  * @author $Author$
  * @version $Rev$
- * @ConQAT.Rating YELLOW Hash: 8BAACE2F49DCFCAFA68F0D0AC25800DB
+ * @ConQAT.Rating YELLOW Hash: 096D8BEE83E5787D24BD8EC4407E4FD4
  */
 public class ConstraintMenu implements IContextMenuContributor {
 
@@ -99,7 +99,7 @@ public class ConstraintMenu implements IContextMenuContributor {
 			};
 			return new ActionContributionItem(a);
 		}
-		if(m.getItems().length == 1) {
+		if(m.getItems().length == 1 && m.getTopActionContribution() != null) {
 			IAction uniqueAction = m.getTopActionContribution().getAction();
 			String txt = m.getMenuText();
 			String newText = txt + " -> " + uniqueAction.getText();
@@ -203,7 +203,10 @@ public class ConstraintMenu implements IContextMenuContributor {
 		 *         contribution and we therefore want to present it without going through a submenu.
 		 */
 		public ActionContributionItem getTopActionContribution() {
-			return moreInfoAction;
+			if(this.getItems()[0] instanceof ActionContributionItem) {
+				return (ActionContributionItem)this.getItems()[0];
+			}
+			return null;
 		}
 
 		/** Action to update a constraint. Assumes the status *can be open*. */