[gtk+] gtkwindow: Fix the comment for an optimization

[Jasper St. Pierre <jstpierre src gnome org>]

commit b7a8bde89581fa1d9aa800828c1347fdb4507aa7
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Jul 15 14:41:04 2014 -0400

    gtkwindow: Fix the comment for an optimization
    
    The optimization was incorrect, and so it was changed in commit
    2bf6824, but the comment to go along with it was never updated.

 gtk/gtkwindow.c |   13 +++++++------
 1 files changed, 7 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index f764bb8..76608d3 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -7155,13 +7155,14 @@ gtk_window_configure_event (GtkWidget         *widget,
       priv->configure_request_count -= 1;
       gdk_window_thaw_toplevel_updates_libgtk_only (gtk_widget_get_window (widget));
     }
-  
-  /* As an optimization, we avoid a resize when possible.
+
+  /* If this is a gratuitous ConfigureNotify that's already
+   * the same as our allocation, then we can fizzle it out.
+   * This is the case for dragging windows around.
    *
-   * The only times we can avoid a resize are:
-   *   - we know only the position changed, not the size
-   *   - we know we have made more requests and so will get more
-   *     notifies and can wait to resize when we get them
+   * We can't do this for a ConfigureRequest, since it might
+   * have been a queued resize from child widgets, and so we
+   * need to reallocate our children in case *they* changed.
    */
   gtk_widget_get_allocation (widget, &allocation);
   if (!expected_reply &&