prevents exception in case of null fix

refs 2553

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

@@ -56,7 +56,7 @@ import org.fortiss.tooling.kernel.ui.service.IModelElementHandlerService;
  * @author hoelzl
  * @author $Author$
  * @version $Rev$
- * @ConQAT.Rating YELLOW Hash: 4C829B509D7118A6E8E6D4625DBEDC48
+ * @ConQAT.Rating YELLOW Hash: 0F49BEEDC5B047EB57A50736B039DA00
  */
 public class ConstraintMenu implements IContextMenuContributor {
 
@@ -209,8 +209,12 @@ public class ConstraintMenu implements IContextMenuContributor {
 		public CheckUnsuccessfulConstraintAction(IConstraint c, IConstrained selectedElt,
 				String prefix) {
 			super(c, selectedElt, prefix, ESharedImages.ERROR_OVERLAY.getImageDescriptor());
-			for(IFix fix : IConstraintVerificationService.INSTANCE.fixes(c.getVerificationStatus())) {
-				this.add(new ActionContributionItem(new FixAction(fix)));
+			List<IFix> fixes =
+					IConstraintVerificationService.INSTANCE.fixes(c.getVerificationStatus());
+			if(fixes != null) {
+				for(IFix fix : fixes) {
+					this.add(new ActionContributionItem(new FixAction(fix)));
+				}
 			}
 		}