First, I'm obligated to say Wineskin isn't supported here. Only pure vanilla Wine is, which is compile yourself and use command line on OSX. You should try Wine version 1.2.3 or 1.3.14 and older to see if there is a difference, since there has been some changes going on with the mouse and pointers from 1.3.15+ that can be problematic. You could also try Screen Options->Override->Fullscreen and/or virtual desktop window, all of which use a Wine virtual desktop, and see if the mouse handles differently. Also check in game to see if there are any Software/Hardware mouse options you can try.
