Video startup on Powerbook (Pismo)

[Raymond Shwake]

I'm running Yellow Dog Linux 2.3 on a G3 Powerbook (Firewire 2000)
set to 1024x768, 24-bit color. I'm attempting to run in a sub-window
set to 800x600. MOL starts up with that setting, I watch everything
load as the desktop builds, then - at the last second - it shrinks
down to what looks like 640x480. The banner shows "Slow Video"
which, as I read the docs, suggests it's dropping down to 8-bit.
But why the windows shrink at the last moment?