Gimp's dockable dialogs always on top

[Harald Hanche-Olsen]

I have this odd problem with gimp. I tried googling and looking for
bug reports describing it, and finding nothing. So I wonder if I am
the only one seeing it?

The problem is with the so-called dochable dialogs, such as the
toolbox and layers and paths dialogs.

The smaller problem is that these always stay on top of other windows,
even if I switch from X11 to some other application. That's annoying,
but can be worked around by running gimp in its own desktop.

Much worse is a related problem with popup menues in these dialogs:
When I activate such a popup, it pops up *under* the corresponding
dialog. Needless to say, this renders gimp just about unusable.

Is anybody else seeing this? I suspect the answer is no, or there
would be howls of frustration. Can you think of ways to investigate
the cause of the problem? Some possibly corrupt config files that I
can remove?

(Should I take this to some gimp mailing list/forum instead?)

This is with gimp @2.8.2_0 on OS X 10.8.2.
I am running XQuartz 2.7.5_rc1, but downgrading to 2.7.4 didn't help.

- Harald