add:  if (! flavourList || flavourList.length < 1) return; 
context:   startDrag: function (aEvent, aDragDropObserver)    {      if (aDragDropObserver.onDragStart)        flavourList = aDragDropObserver.onDragStart(aEvent);      var trans = nsTransferable.set(flavourList);      trans = trans ? trans.QueryInterface(Components.interfaces.nsISupports) : trans;      var transArray = nsJSSupportsUtils.createSupportsArray();      transArray.AppendElement(trans);            var dragServiceIID = Components.interfaces.nsIDragService;      this.mDragService.invokeDragSession(aEvent.target, transArray, null,                                           dragServiceIID.DRAGDROP_ACTION_COPY + dragServiceIID.DRAGDROP_ACTION_MOVE);      aEvent.preventBubble();    },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/ff5f24368cd6faebb5a51027a83f90820bfdbd5f/nsDragAndDrop.js/buggy/xpfe/global/resources/content/nsDragAndDrop.js