Avoid ConcurrentModificationException in MarkerService::UIJob

Issue-Ref: 4339
Issue-Url: af3#4339



Signed-off-by: Simon Barner <barner@fortiss.org>

org.fortiss.tooling.kernel.ui/src/org/fortiss/tooling/kernel/ui/internal/.ratings

 ActionService.java e29126b5947c9fd2f1d82bb87001b9d0ead50c3b GREEN
 ContextMenuService.java 752ecb95721c4ff31583095bdb06b71ef28c4dcf GREEN
-MarkerService.java 5cc84f9c1e9811100fad92c0abfa934613173c06 GREEN
+MarkerService.java 9715b5ef55ba8c81759dbb914d99a018fcdd2429 GREEN
 ModelEditorBindingService.java f304addb514cd2de443997e0b52cef7a3a9897bf GREEN
 ModelElementHandlerService.java 34adeef844bf98c69f1b9a7252f34d0a2b741b54 GREEN
 NavigatorService.java 1d773dde3791ddf7051616fe249558e7e307757d GREEN

org.fortiss.tooling.kernel.ui/src/org/fortiss/tooling/kernel/ui/internal/MarkerService.java

@@ -265,7 +265,9 @@ public class MarkerService implements IMarkerService, IPersistencyServiceListene
 			public IStatus runInUIThread(IProgressMonitor monitor) {
 				for(EObject eo : violationsMap.keySet()) {
 					postRefreshNotification(eo);
-					for(IConstraintViolation<? extends EObject> viol : violationsMap.get(eo)) {
+					// Create copy of list since it might be updated in parallel to the UI update.
+					for(IConstraintViolation<? extends EObject> viol : new ArrayList<>(
+							getCachedList(eo))) {
 						postRefreshNotification(viol.getSource());
 					}
 				}