rem: prefs.removeObserver("extensions.firebug", FirebugPrefsObserver); 
add: prefs.removeObserver("extensions.firebug", FirebugPrefsObserver); 
context:     shutdown: function()    {		prefs.removeObserver("extensions.firebug", FirebugPrefsObserver);        timer = null;        fbs = null;        jsd = null;    },
meta: 7450	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/7450/2e2e6e5e5acba26e69243682fad1c16a0bea8a6a/firebug-service.js/buggy/extension/components/firebug-service.js