Gnome desktop, terminal problems in overlay (8+24-bit) mode.

[kend xanoptix com]

Hello, all.  I just got overlay mode working on my MGA dual-head (via two
cards) setup, and it's got some problems:

1) The Gnome panel and Nautilus desktop background are both in 8-bit color mode.
2) My Gnome terminal (using monospace 10 with custom colors) and xterms have
   suddenly had all the text vanish.  I can't even cause highlighting with the
   mouse where the text is to make it go reverse-video.  (Though the text does
   paste just fine from the "clipboard", so I -know- it's there.)

Other apps -- eg., Mozilla, the Gimp -- work fine.

Any ideas/suggestions?  I've Googled some, but haven't found anything that
might actually help to remedy these issues.

Thanks,

Ken D'Ambrosio