Windowed DirectX apps seem to be freaking out on my Windows 7 install. Specifically Halo CE and Battlefront II.
The mouse turns invisible when the windowed game has the foreground, but continues to track on the desktop, randomly activating tooltips and the Aero Peek feature. VERY annoying to say the least.
Is there a way to work around this? Not an issue in Windows XP.
Update
Only happens when running Windows Media Player (even audio, no video renderer is required).