rem: if (GetMessagePaneFrame().currentURI != "about:blank") GetMessagePaneFrame().loadURI("about:blank"); 
add: if (GetMessagePaneFrame().location != "about:blank") GetMessagePaneFrame().location = "about:blank"; 
context: function ClearMessagePane(){	if(gHaveLoadedMessage)	{	    gHaveLoadedMessage = false;		gCurrentDisplayedMessage = null;		if (GetMessagePaneFrame().currentURI != "about:blank")		  GetMessagePaneFrame().loadURI("about:blank");		    // hide the message header view AND the message pane...		HideMessageHeaderPane();	}}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/23bbbdbeb7a7f3ae77cad3bd747dcb2381d9f3e3/msgMail3PaneWindow.js/clean/mailnews/base/resources/content/msgMail3PaneWindow.js