Hi,

FWIW, here's an old wm-spec-list thread on this topic:
 http://mail.gnome.org/archives/wm-spec-list/2002-May/msg00030.html

I like Lubos's approach, to use window role. I can't find any mention
of that in the wm-spec-list thread, I don't know why no one thought of
it back then.

Havoc