rem: var observerSvc = Cc["@mozilla.org/observer-service;1"]. getService(Ci.nsIObserverService); 
add: var observerSvc = Components.classes["@mozilla.org/observer-service;1"] .getService(Components.interfaces.nsIObserverService); 
context: function imipOnUnload(){    removeEventListener("messagepane-loaded", imipOnLoad, true);    removeEventListener("messagepane-unloaded", imipOnUnload, true);    var observerSvc = Cc["@mozilla.org/observer-service;1"].                      getService(Ci.nsIObserverService);    observerSvc.removeObserver(onItipItem, "onItipItemCreation");    gItipItem = null;}
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/9421/38f660b3db40758b875dea97231a8bd5e83200b2/imip-bar.js/buggy/calendar/lightning/content/imip-bar.js