rem: return; 
add: return false; 
context: function DragOverTree(event){  if (event.target.localName != "treecell" &&       event.target.localName != "treeitem") {            event.preventBubble();    return;  }	var validFlavor = false;	var dragSession = null;	var dragService = GetDragService();	if ( !dragService )	return(false);	dragSession = dragService.getCurrentSession();	if ( !dragSession )	return(false);	if ( dragSession.isDataFlavorSupported("text/nsmessage") )	validFlavor = true;	//XXX other flavors here...	// touch the attribute on the treeItem to trigger the repaint with the drop feedback	// (recall that it is two levels above the target, which is a treeCell).	if ( validFlavor )	{		//XXX this is really slow and likes to refresh N times per second.		event.target.parentNode.parentNode.setAttribute ( "dd-triggerrepaint", 0 );		dragSession.canDrop = true;		event.preventBubble();  // do not propagate message	}}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/1b225ed4083c0eae61d6c7858de6e131bf4de3b9/messengerdnd.js/buggy/mailnews/base/resources/content/messengerdnd.js