The mouse appears for me too, and I haven't found a way to get rid of it, except move it out of the way :-/
<Obligatory run-on sentence rant>
Since a front-end is designed to launch emulators, and there are a lot more emulators than there are front ends, it seems to me that this feature, along with setting an exit key (a-la generic command-line wrapper) are functions that should be moved up to the FE level.
</Obligatory run-on sentence rant>
-Steve