add: this.mCurrentDropPosition = this.determineDropPosition(aEvent); 
context:   onDragEnter: function (aEvent, aDragSession)  {    var target = aEvent.target;    if (target.localName == "menupopup" || target.localName == "hbox")      target = target.parentNode;    if (aDragSession.canDrop) {      this.onDragSetFeedBack(aEvent);      this.onDragEnterSetTimer(target, aDragSession);    }    this.mCurrentDragOverTarget = target;    return;  },
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/d40c083d1e906f66622155f2f6c1915178d1c0a9/navigatorDD.js/clean/xpfe/browser/resources/content/navigatorDD.js