You're using one of these Intel video cards, yeah? Cuz that shortcut is from your video card, not your Quark.
Same thing here, my mobo has an Intel 82835 (think) video card, on board.
I think that other video cards have the same utility (e.g., Nvidia has something like that but the shurtcut is different).
If you don't want thins to happen, click on the icon of the video in the system tray, right click after, and choose to disable the shortcut keys.