Index: gtk/gtkrange.c
===================================================================
--- gtk/gtkrange.c	(revision 18542)
+++ gtk/gtkrange.c	(working copy)
@@ -1569,9 +1569,12 @@
 
   gtk_widget_queue_draw (GTK_WIDGET (range));
   /* This is so we don't lag the widget being scrolled. */
+#if 0
+  /* Disable this, the scroll bar lags a bit but the end result is that
+     scrolling treeviews is *a lot* smoother. See GNOME #460534. */
   if (GTK_WIDGET_REALIZED (range))
     gdk_window_process_updates (GTK_WIDGET (range)->window, FALSE);
-  
+#endif
   /* Note that we don't round off to range->round_digits here.
    * that's because it's really broken to change a value
    * in response to a change signal on that value; round_digits