What's the point of the MouseWindow function, exactly? How does it work? I've mirrored the position of the player display and menu in the PlayerClassMenu, and problems seem to be occurring whether I include it or not, when I'm using build r2785.
Here's a crash report I get when hovering the mouse cursor near the player display (or above the player class menu).
And here's a crash I get when pressing 'Back' on the skill select screen (to take me back to the player class menu). I suspect these two reports are very much the same.
Run this wad.