rem: if (GetMessagePaneFrame().location != "about:blank") GetMessagePaneFrame().location = "about:blank"; 
add: if (GetMessagePaneFrame().location.href != "about:blank") GetMessagePaneFrame().location.href = "about:blank"; 
context: function ClearMessagePane(){  if(gHaveLoadedMessage)  {    gHaveLoadedMessage = false;    gCurrentDisplayedMessage = null;    if (GetMessagePaneFrame().location != "about:blank")        GetMessagePaneFrame().location = "about:blank";        // hide the message header view AND the message pane...    HideMessageHeaderPane();    gMessageNotificationBar.clearMsgNotifications();  }}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/cddca7b1217f1f1a10c371a975c199b3efbaa9cc/msgMail3PaneWindow.js/clean/mail/base/content/msgMail3PaneWindow.js