Running a full screen game in a XP guest, wierd interlacing

[jeffadams78]

I am trying to run a windows game, "Divine Divinity", in an XP guest (OSX 10.6 host).

I'm running the latest release (the "fixed" one) of VBox.

When it goes to "full screen" mode (game goes to 800x600), instead of being "full screen" in windows, it is this weird screen where it appears to be interlacing one line of desktop with one line of game. I'm attaching a screen shot (of only the lower 1/3 of the screen unfortunately due to the file attachment size limits, but it's enough for you to see what I'm talking about).

The game has three graphics modes, Direct3d (which doesn't work at all), DirectDraw and "Software". DirectDraw and Software both behave exactly the same, which makes me somewhat suspicious that it is something wrong in VBox and/or my XP setup rather than the game itself. Unfortunately I don't have any other "full screen" games to try for comparison.

Anyone else experienced anything like this?