Filed many bugs this past weekend to get raiseless DnD support in GNOME, and grouped them with a meta-bug. I split them too finely, so Owen promptly marked some as duplicates of others. All the Gtk+ bugs are on the 2.6 API freeze target milestone. Thanks to some earlier work and Matthias Clasen, there's already a patch which makes most of the necessary changes to Gtk+. The Metacity bugs have patches attached too, though they're the minimum needed (three lines) to get the right behavior and less than ideal.