private SModelNodeListeners getModelListeners() {
   if (myModelListeners == null) {
     myModelListeners =
         new SModelNodeListeners(myGenStatusVisitor, myErrorVisitor, myModifiedMarker);
     myModelListeners.startListening();
   }
   return myModelListeners;
 }
 public void dispose() {
   myTree.removeTreeNodeListener(myNodeListener);
   if (myModuleListeners != null) {
     myModuleListeners.stopListening();
     myModuleListeners = null;
   }
   if (myModelListeners != null) {
     myModelListeners.stopListening();
     myModelListeners = null;
   }
   myGenStatusVisitor.setUpdater(null).setExecutor(null);
   myErrorVisitor.setUpdater(null).setExecutor(null);
   myModifiedMarker.setUpdater(null).setExecutor(null);
 }