Minimized Emacs and Gnome logout

[Chong Yidong]

1. Run Emacs in Gnome
2. Iconify (minimize) the Emacs window,
     (e.g. by clicking on its taskbar entry)
3. Gnome menu -> Quit -> Log Out
4. Nothing happens.
5. Now de-iconify Emacs (e.g. by clicking on its taskbar entry).
6. Gnome logs out.

`kill' and `kill -9' seem to work fine on the iconified Emacs, so is
there some other signal that the Gnome logout sends that we are not
responding properly to?

FWIW, I'm using the version of Gnome that comes with Ubuntu Dapper.
This behavior has been present for several months, but I haven't been
able to identify the problem.