add: osvr.removeObserver(this, "browser:purge-session-history"); 
context:   _dispose: function()   {    // observer removal     const osvr = Components.classes['@mozilla.org/observer-service;1']                           .getService(Components.interfaces.nsIObserverService);    osvr.removeObserver(this, "profile-change-teardown");    osvr.removeObserver(this, "xpcom-shutdown");    osvr.removeObserver(this, "final-ui-startup");  },
meta: 8395	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/8395/15076987ab622b120a36fac133e376d4684af683/nsBrowserGlue.js/clean/browser/components/nsBrowserGlue.js