Assuming for now that this is still relevant, although the last comment by the reporter was a year and a half ago.
Bryce, I'm not quite sure if I understand your comment above. You mention that this is not an issue with -radeon, as it only occurs when VirtualBox is running, and VirtualBox uses a different video driver. If I read the reporter's comments correctly though, VirtualBox is running as an application under a host X server using the ATI video driver, and this is not a case of Ubuntu running inside VirtualBox using the VirtualBox driver - the reporter said that they are using Windows XP as a guest system. It may still be VirtualBox-related, but surely not to the VirtualBox video driver?
Assuming for now that this is still relevant, although the last comment by the reporter was a year and a half ago.
Bryce, I'm not quite sure if I understand your comment above. You mention that this is not an issue with -radeon, as it only occurs when VirtualBox is running, and VirtualBox uses a different video driver. If I read the reporter's comments correctly though, VirtualBox is running as an application under a host X server using the ATI video driver, and this is not a case of Ubuntu running inside VirtualBox using the VirtualBox driver - the reporter said that they are using Windows XP as a guest system. It may still be VirtualBox-related, but surely not to the VirtualBox video driver?