I just installed GroovyArcade using the 12/24/2014 Beta distro.
I have an X-Arcade trackball that works fine in X, full motion, etc. However, when I launch a game such as Centipede, the mouse only partially works. Up and down behaves normally, and right works normally, however, left doesn't work correctly. It behaves as if the left limit of the screen is moved. For example, if the character is on the left side of the screen, I can move it to the right. Then, I can move it a little bit to the left, but not all the way. The further to the right the character moves, the more left is limited.
It isn't a hardware issue. If I connect this trackball to a different MAME machine, it functions correctly, so it seems to be software related.
Anyone experienced anything like this before?