add: return false; if (aFolder.Value == "NC:BookmarksTopRoot") 
context:   isValidTargetContainer: function (aFolder, aSelection)  {    if (!aFolder)      return false;    if (aFolder.Value == "NC:BookmarksRoot")      return true;    // don't insert items in an invalid container    // 'file:' and 'find:' items have a 'Bookmark' type    var type = BookmarksUtils.resolveType(aFolder);    if (type != "Folder" && type != "FolderGroup" && type != "PersonalToolbarFolder")      return false;    // bail if we just check the container    if (!aSelection)      return true;    // don't insert folders in a group folder except for 'file:' pseudo folders    if (type == "FolderGroup")      for (var i=0; i<aSelection.length; ++i)        if (aSelection.isContainer[i] && aSelection.protocol[i] != "file")          return false;    // check that the selected folder is not the selected item nor its child    if (this.isContainerChildOrSelf(aFolder, aSelection))      return false;    return true;  },
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/717feaab4a55cf603c3c58a335746d5fdbe3ba8e/bookmarks.js/buggy/xpfe/components/bookmarks/resources/bookmarks.js