Hi.
I have an iMac 10.6.4, Nvidia GeForce 7300 GT, 128 vram, 1gb ram
I'm running Crossover Games 9.1
I have Stalker: Shadow of Chernobyl on Steam. My steam updated the other day, and Stalker works for me as well as it did before: meaning the mouse is temporarily stuck at the bottom. If I move my mouse really fast on the menu screen, I can briefly see it.
Try using the arrow keys to navigate to the Options tab on the Stalker menu. Now, before, I had to actually HIT the Fullscreen box to uncheck it. Meaning I would put my mouse on a large book and try to run it up the screen and then -click-click-click- as it came down, hoping to hit that tiny little box because the mouse will work in windowed mode (though I personally had video resolution problems). Now however, all I have to do is hit the USE button good and solid, and that's good because it's a lot easier to hit. Once I've done that, I can keep playing in full-screen and the mouse works and I have no nasty GIANT CURSOR graphics errors (that have plagued a few of my games).
So anyway, try to see if you can navigate to Options and see if running your mouse will temporarily unstick it from the bottom and try to hit that USE button. See if that works for you.