add:  this._dragCache.sourceTopLevel = this._dragCache.sourceWidget.getTopLevelWidget(); 
context: proto._handleMouseDown = function(e){  if (e.getDefaultPrevented()) {    return;  };  // Store initial dragCache  this._dragCache = {    startScreenX: e.getScreenX(),    startScreenY: e.getScreenY(),    pageX: e.getPageX(),    pageY: e.getPageY(),    sourceWidget: e.getTarget(),    dragHandlerActive: false,    hasFiredDragStart: false  };};
meta: 1005	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/1005/1bde26c43e1c5aed1a1373cd64593467db457744/QxDragAndDropManager.js/clean/qooxdoo/source/script/managers/QxDragAndDropManager.js