[gtk+] Clarify comment

[Alexander Larsson <alexl src gnome org>]

commit e25ac0b5cbf9c8b3b8ff3dd7c4bf22f8f480132f
Author: Alexander Larsson <alexl redhat com>
Date:   Thu Aug 13 13:35:58 2009 +0200

    Clarify comment

 gdk/gdkwindow.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index 211d672..eaca781 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -2981,8 +2981,8 @@ append_move_region (GdkWindowObject *impl_window,
     }
 }
 
-/* Moves bits and update area by dx/dy in impl window,
-   takes ownership of region */
+/* Moves bits and update area by dx/dy in impl window.
+   Takes ownership of region to avoid copy (because we may change it) */
 static void
 move_region_on_impl (GdkWindowObject *private,
 		     GdkRegion *region, /* In impl window coords */