FreeBSD and Xorg: session ending ends up in locked up Xorg server

[O. Hartmann]

Hello,

I have a strange problem on one of my FreeBSD 7.0-STABLE boxes.

The machine is a FreeBSD 7.0-STABLE/AMD64 box, most recently built-world.
Whenever I logout from a local X11 session (using Xorg, most recent, and 
Windowmaker, also most recent, all X stuff recently rebuilt), Xorg eats 
up 100% CPU time and I never get back to the login box offered by xdm 
(xdm is driven by /etc/ttys as recommended). Instead I see a weird 
unresponsive screen with blinking, weird coloured block-graphics and 
letters, in most cases the same pattern, but this changes. Logging in 
from another box and killing Xorg gives back the expected login box from 
xdm.

I have no glue what's going on here. My graphics board is a nVidia 
driven GF8600GTS and it worked well a couple of weeks ago. I rebuild the 
whole X stuff incl. all the dependencies because I thought it could have 
something to do with miscompiled or outdated ports - but thta isn't 
obviously the fact.

Does anyone see this on his box also?

Regards,
Oliver