Rotated secondary display does not refresh properly under Windows 7 or Ubuntu guest

Today I physically rotated my secondary widescreen display into portrait mode, and then selected the appropriate rotation option in the Displays preferences under Mac OS X. Everything seems to be working fine under Mac OS X, but when I run a Windows 7 (or Ubuntu 10.10) guest VM, this secondary display doesn't refresh properly. The Windows/Linux desktop appears, and I can drag windows onto the secondary display, but from then on, the secondary display doesn't refresh. For instance, while the mouse cursor appears, any keystrokes entered into these windows do not. Right-clicking on the desktop does not cause the context menu to appear, until I move my mouse cursor back over to the primary display and click on the desktop there. Then the context menu appears for a split second on the secondary display and immediately disappears in response to the click on the primary display. Again, this is happening under both Windows 7 and Ubuntu, and both of these VMs render on the second display properly if I change the rotation from 90 degrees back to 0. Is there some way to work around this?