LinuxQuestions.org - Odd gtk theme issue, inconsistent between wm sessions

This is highly odd. First some background...

I'm using Mandrake 9.1, which comes with Gnome2, so I was not very
surprised when the Gnome control panel only lets me change the theme
for GTK2 apps, and of course, GTK 1.x apps (e.g., Gimp) don't use it.
So I went looking for a way to change the GTK theme from the command
line, found one, and told it to apply the thEmacs theme that I liked when
I was using Gnome1 (on a different install).

Apps didn't use the new theme, and I figured the tool didn't work -- but
I was (partly) wrong (I think). I finally got utterly fed up with metacity
and started trying out other sessions besides Gnome. When I tried
icewm, lo and behold, my GTK apps were picking up and using the
thEmacs theme that I had applied.

But under gnome-session that doesn't happen; GTK apps get the default
theme or whatever. I tried other window manager sessions, and most of
them do what Gnome does, but a couple do what icewm does. And KDE
makes a sort of hybrid, which looks really funky. (Screenshots available
upon request.)

So here's my question: what's different under gnome-session (even if
I change the window manager to icewm via killall metacity; icewm &)
than under the icewm session, that causes Gimp and other GTK apps
to pick up a different GTK theme -- and, more importantly, how do I
get the theme installed so that it will be used under all sessions? Now
that I've got sawfish installed, I'd like to go back to the Gnome session,
but the inability to get GTK apps to use a sensible theme (no blinding
white backgrounds) is crucial.

No, I do not have multiple versions of Gimp installed.

TIA for any assistance.