Fix document title's not being synced properly.

AppKit/CPWindow/CPWindow.j

@@ -1834,11 +1834,11 @@ CPTexturedBackgroundWindowMask
 */
 - (void)becomeMainWindow
 {
+    CPApp._mainWindow = self;
+
     [self _synchronizeMenuBarTitleWithWindowTitle];
     [self _synchronizeSaveMenuWithDocumentSaving];
 
-    CPApp._mainWindow = self;
-
     [[CPNotificationCenter defaultCenter]
         postNotificationName:CPWindowDidBecomeMainNotification
                       object:self];