I had the same problem & I can no longer reproduce this bug on lucid.
stefan@rosa:~$ lspci -nn | grep VGA 01:00.0 VGA compatible controller [0300]: ATI Technologies Inc Radeon RV250 [Mobility FireGL 9000] [1002:4c66] (rev 01)
stefan@rosa:~$ uname -a Linux rosa 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux
I had the same problem & I can no longer reproduce this bug on lucid.
stefan@rosa:~$ lspci -nn | grep VGA
01:00.0 VGA compatible controller [0300]: ATI Technologies Inc Radeon RV250 [Mobility FireGL 9000] [1002:4c66] (rev 01)
stefan@rosa:~$ uname -a
Linux rosa 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux