rem: isValid = BookmarksUtils.isSelectionValidForInsertion(aSelection, aTarget); 
add: var isValid = BookmarksUtils.isSelectionValidForInsertion(aSelection, aTarget); 
context:   insertAndCheckSelection: function (aAction, aSelection, aTarget, aTargetIndex)  {    isValid = BookmarksUtils.isSelectionValidForInsertion(aSelection, aTarget);    if (!isValid) {      SOUND.beep();      return false;    }    this.insertSelection(aAction, aSelection, aTarget, aTargetIndex);    BookmarksUtils.flushDataSource();    return true;  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/c2bd24c3f13f8efa0f1b478893ff3da733ff48da/bookmarks.js/buggy/browser/components/bookmarks/content/bookmarks.js