Bug #326846 read mail not marked as read from the stand alone message window.

Fix a JS error that was causing this problem from Bug 183394.
sr=bienvenu

mail/base/content/mailWindowOverlay.js

@@ -2318,7 +2318,7 @@ function OnMsgLoaded(aUrl)
 
     var folder = aUrl.folder;
     var msgURI = GetLoadedMessage();
-    var msgHdr = null;
+    var msgHdr = null;
     
     if (!folder || !msgURI)
       return;
@@ -2328,10 +2328,9 @@ function OnMsgLoaded(aUrl)
     // and the selection does not "snap back" to the message chosen by
     // SetNextMessageAfterDelete() when the operation completes (bug 243532).
     // But the just loaded message might be getting deleted, if the user
-    // deletes it before the message is loaded (bug 183394)
-    var treeSelection = GetThreadTree().view.selection;
-
-    if (treeSelection.currentIndex != gSelectedIndexWhenDeleting)
+    // deletes it before the message is loaded (bug 183394)
+    var wintype = document.documentElement.getAttribute('windowtype');
+    if (wintype == "mail:messageWindow" || GetThreadTree().view.selection.currentIndex != gSelectedIndexWhenDeleting)
       gNextMessageViewIndexAfterDelete = -2;
 
     if (!(/type=application\/x-message-display/.test(msgURI)))
@@ -2346,7 +2345,6 @@ function OnMsgLoaded(aUrl)
 
     if (msgHdr && !msgHdr.isRead)
     {
-      var wintype = document.documentElement.getAttribute('windowtype');
       if (markReadOnADelay && wintype == "mail:3pane") // only use the timer if viewing using the 3-pane preview pane and the user has set the pref
       {
         ClearPendingReadTimer();