prevents posting refresh notification to null

refs 2620

org.fortiss.tooling.kernel.ui/trunk/src/org/fortiss/tooling/kernel/ui/util/ConstraintsUIUtils.java

@@ -48,7 +48,7 @@ import org.fortiss.tooling.kernel.utils.EcoreUtils;
  * @author aravantinos
  * @author $Author$
  * @version $Rev$
- * @ConQAT.Rating YELLOW Hash: 9ED423BE05D3E18DB01F266CE969FFFE
+ * @ConQAT.Rating YELLOW Hash: 1A2E05793B7CC8550EA7BDB66D728AEA
  */
 public class ConstraintsUIUtils {
 
@@ -161,8 +161,11 @@ public class ConstraintsUIUtils {
 		for(ConstrainedWithChecksum cwc : c.getConstrainedsWithChecksum()) {
 			constraineds.add(cwc.getConstrained());
 		}
-		constraineds.stream().forEach(
-				constrained -> EcoreUtils.postRefreshNotification(constrained));
+		constraineds.stream().forEach(constrained -> {
+			if(constrained != null) {
+				EcoreUtils.postRefreshNotification(constrained);
+			}
+		});
 	}
 
 	/**