rem: document.getElementById("bookmarks-menu").parentNode, 
add: #       menubar menus haven''t an "open" attribute: we can take the child document.getElementById("bookmarks-menu").firstChild, 
context:   get mObservers ()  {    if (!this._observers) {      this._observers = [        document.getElementById("bookmarks-ptf"),        document.getElementById("bookmarks-menu").parentNode,        document.getElementById("bookmarks-chevron").parentNode      ]    }    return this._observers;  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/0be63656d1e4c89a81ff7a928785682e671765a9/bookmarksMenu.js/buggy/browser/components/bookmarks/content/bookmarksMenu.js