add: pbi.removeObserver(gURLBarAutoFillPrefListener.domain, gURLBarAutoFillPrefListener); 
context: function Shutdown(){  var os = Components.classes["@mozilla.org/observer-service;1"]    .getService(Components.interfaces.nsIObserverService);  os.removeObserver(gSessionHistoryObserver, "browser:purge-session-history");  os.removeObserver(gBrowser.browsers[0], "browser:purge-session-history");#ifdef MOZ_ENABLE_XREMOTE  // remove remote support  var remoteService;  remoteService = Components.classes["@mozilla.org/browser/xremoteservice;1"]                            .getService(Components.interfaces.nsIXRemoteService);  remoteService.removeBrowserInstance(window);  os.removeObserver(gTabOpenObserver, "open-new-tab-request");#endif  try {    gBrowser.removeProgressListener(window.XULBrowserWindow);  } catch (ex) {  }  var bt = document.getElementById("bookmarks-ptf");  if (bt) {    try {      bt.database.RemoveObserver(BookmarksToolbarRDFObserver);      bt.controllers.removeController(BookmarksMenuController);    } catch (ex) {    }  }  try {    var bm = document.getElementById("bookmarks-menu");    bm.controllers.removeController(BookmarksMenuController);  } catch (ex) {  }  try {    var pbi = gPrefService.QueryInterface(Components.interfaces.nsIPrefBranchInternal);    pbi.removeObserver(gFormFillPrefListener.domain, gFormFillPrefListener);    pbi.removeObserver(gHomeButton.prefDomain, gHomeButton);  } catch (ex) {  }  BrowserOffline.uninit();  var windowManager = Components.classes['@mozilla.org/appshell/window-mediator;1'].getService();  var windowManagerInterface = windowManager.QueryInterface(Components.interfaces.nsIWindowMediator);  var enumerator = windowManagerInterface.getEnumerator(null);  enumerator.getNext();  if (!enumerator.hasMoreElements()) {    document.persist("sidebar-box", "sidebarcommand");    document.persist("sidebar-box", "width");    document.persist("sidebar-box", "src");    document.persist("sidebar-title", "value");  }  window.XULBrowserWindow.destroy();  window.XULBrowserWindow = null;  window.browserContentListener.close();  // Close the app core.  if (appCore)    appCore.close();}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/79d464768a1b144b75978aff33413a2f1e00313f/browser.js/buggy/browser/base/content/browser.js