add: var pbi = prefService.getBranch(""); pbi = pbi.QueryInterface(Components.interfaces.nsIPrefBranchInternal); pbi.removeObserver("calendar.category.color.", categoryPrefObserver);  
context: function calendarFinish(){   finishCalendarUnifinder();      finishCalendarToDoUnifinder();   gCalendarWindow.close();   gICalLib.removeObserver( gEventSource.alarmObserver );}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/09075d6591427a6f64421ad386c865deb5a0f14f/calendar.js/clean/calendar/resources/content/calendar.js