Ok, as of 1.3.23, the I'm seeing behavior is as ertdfg22 described.
If I set "MouseWarpOverride"="disable" then the mouse
immediately gets stuck on the first screen in the lower left corner after a
little jumping around. If I set
"MouseWarpOverride"="enable", everything appears to work
fine on the first screen, but when I select "Load a Saved Game" then
suddenly returns to the aforementioned "disable" behavior where the
mouse jumps around briefly and gets stuck in the lower left corner. I can't
load a saved game to see what the mouse behavior is in the game itself.
Downgrading to Wine 1.2.3 works fine.
Is the status of the new mouse behavior pretty much stable now? Should I open a
bug for this?