             contentGroupProperties = newContentGroupProperties;
             
             contentGroup.addEventListener(
-                ItemExistenceChangedEvent.ITEM_ADD, contentGroup_itemAddedHandler);
+                ElementExistenceEvent.ELEMENT_ADD, contentGroup_elementAddedHandler);
             contentGroup.addEventListener(
-                ItemExistenceChangedEvent.ITEM_REMOVE, contentGroup_itemRemovedHandler);
+                ElementExistenceEvent.ELEMENT_REMOVE, contentGroup_elementRemovedHandler);
             contentGroup.addEventListener(
                 PropertyChangeEvent.PROPERTY_CHANGE, contentGroup_propertyChangeHandler);
             
             if (_placeHolderGroup)
             {
                 _placeHolderGroup.removeEventListener(
-                    ItemExistenceChangedEvent.ITEM_ADD, contentGroup_itemAddedHandler);
+                    ElementExistenceEvent.ELEMENT_ADD, contentGroup_elementAddedHandler);
                 _placeHolderGroup.removeEventListener(
-                    ItemExistenceChangedEvent.ITEM_REMOVE, contentGroup_itemRemovedHandler);
+                    ElementExistenceEvent.ELEMENT_REMOVE, contentGroup_elementRemovedHandler);
                 
                 _placeHolderGroup = null;
             }

        if (instance == contentGroup)
        {
            contentGroup.removeEventListener(
                ItemExistenceChangedEvent.ITEM_ADD, contentGroup_itemAddedHandler);
            contentGroup.removeEventListener(
                ItemExistenceChangedEvent.ITEM_REMOVE, contentGroup_itemRemovedHandler);
            contentGroup.removeEventListener(
                PropertyChangeEvent.PROPERTY_CHANGE, contentGroup_propertyChangeHandler);
            

                
            contentGroupProperties = newContentGroupProperties;
            
            var myMxmlContent:Array = contentGroup.mxmlContent;
            
            if (myMxmlContent)
            {
                _placeHolderGroup = new Group();
                     
                _placeHolderGroup.mxmlContent = myMxmlContent;
                
                _placeHolderGroup.addEventListener(
                    ElementExistenceEvent.ELEMENT_ADD, contentGroup_elementAddedHandler);
                _placeHolderGroup.addEventListener(
                    ElementExistenceEvent.ELEMENT_REMOVE, contentGroup_elementRemovedHandler);
            }
            
            // TODO: Need to force the contentGroup to removeChild on its content children
