rem: aEvent.preventBubble(); 
add: aEvent.stopPropagation(); 
context:   dragOver: function (aEvent, aDragDropObserver)    {       if (!("onDragOver" in aDragDropObserver))         return;      if (!this.checkCanDrop(aEvent, aDragDropObserver))        return;      var flavourSet = aDragDropObserver.getSupportedFlavours();      for (var flavour in flavourSet.flavourTable)        {          if (this.mDragSession.isDataFlavorSupported(flavour))            {              aDragDropObserver.onDragOver(aEvent,                                            flavourSet.flavourTable[flavour],                                            this.mDragSession);              aEvent.preventBubble();              break;            }        }    },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/04cfde2d6fd8dbf1abe2b7ec6ca8d6cbb0386d6d/nsDragAndDrop.js/clean/xpfe/global/resources/content/nsDragAndDrop.js