Why does my Geometry pallet keep disappearing in Vista?
How to Avoid Strange GibbsCAM Display Behavior When Running Under Windows Vista
Some GibbsCAM installations have experienced a problem where dialogs disappear on Windows Vista. In this case it may be helpful to disable desktop composition. To do this, bring up the properties dialog on the GibbsCAM executable file, click on the compatibility tab and check “Disable Desktop Composition”.