add: document.getElementById("fullScreenItem").setAttribute("checked", !window.fullScreen); 
context:   toggle: function()  {    // show/hide all menubars, toolbars, and statusbars (except the full screen toolbar)    this.showXULChrome("toolbar", window.fullScreen);    this.showXULChrome("statusbar", window.fullScreen);  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/bd450ea07fb3fa5fff08e4dee86fad21d860afb8/browser.js/buggy/browser/base/content/browser.js