add: pref.removeObserver("mail.showCondensedAddresses", MsgHdrViewObserver);  
context: function OnUnloadMsgHeaderPane(){  // dispatch an event letting any listeners know that we have unloaded the message pane  var event = document.createEvent('Events');  event.initEvent('messagepane-unloaded', false, true);  var headerViewElement = document.getElementById("msgHeaderView");  headerViewElement.dispatchEvent(event);}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/5a877292e3dac6564d8ff384d425e5c1ed4c9b7a/msgHdrViewOverlay.js/buggy/mail/base/content/msgHdrViewOverlay.js