hehe, you've just enountered wierd bug #100843....
okay, so we don't exactly track the bugs, but the 1600x1200 screen res is notorious for causing wierd problems like the one you mentioned. i'd just go with a lower res and be done with it.
and if they use a different graphics engine for the next game, you can count on that problem not being present.
See the struggle of the faithless lot as they negate their time
How low to sink to the depths of their frame of mind