add:  msgWindow.closeWindow(); 
context: function OnUnloadMessenger(){	dump("\nOnUnload from XUL\nClean up ...\n");	var mailSession = Components.classes[mailSessionProgID].getService();	if(mailSession)	{		mailSession = mailSession.QueryInterface(Components.interfaces.nsIMsgMailSession);		if(mailSession)		{			mailSession.RemoveFolderListener(folderListener);			mailSession.RemoveMsgWindow(msgWindow);			messenger.SetWindow(null, null);		}	}}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/d7ca46f6a5ac7c4ccc4c84e0e23b81132eff05be/msgMail3PaneWindow.js/clean/mailnews/base/resources/content/msgMail3PaneWindow.js