Display problems with "Desktop Composition" in Windows Vista/7

In Windows Vista, "Desktop Composition" has to be disabled if you notice display problems. Right click on the Atena3D and 2D items in the start menu, select Properties, then the Compatibility tab. Check the box "Disable desktop composition".
In some cases, changing the display theme (Control Panel - Appearance and Personalization - Personalization - Theme) to "Windows Classic" can also help with display problems.