rem: if (!(doc instanceof XMLDocument)) 
add: if (!(doc instanceof XMLDocument) &&  !(doc instanceof XULDocument)) 
context:   _validate: function(doc) {    // See if the document is XML.  If not, it's definitely not a feed.    if (!(doc instanceof XMLDocument))      return false;          // See if the document we're dealing with is actually a feed.    if (!this._isDocumentFeed(doc.documentElement))      return false;    // Make sure the document is loaded into one of the browser tabs.    // Otherwise, it might have been loaded as data by some application    // that expects it not to change, and we shouldn't break the app    // by changing the document.    var feedURI =         Components.classes["@mozilla.org/network/io-service;1"].        getService(Components.interfaces.nsIIOService).        newURI(doc.location.href, null, null);    if (!this._getContentShell(doc, feedURI))      return false;    return true;  },
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/8e5c60ebf0227995bcf9f5d13a80607148f1b604/browser.js/buggy/browser/base/content/browser.js