add: return null; 
context:   QueryInterface : function(iid)    {    if(iid.equals(Components.interfaces.nsIXULBrowserWindow))      return this;    throw Components.results.NS_NOINTERFACE;    },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/7d436f5eb0dc3a28eb87b875adc9cf608948cda4/mini-nav.js/buggy/embedding/browser/chrome/content/mini-nav.js