Cursor stuck as pinwheel/beachball

[.psd]

But it's not spinning. And it only happens when I load 'Dota 2', but once it starts, NOTHING I've done short of restarting the machine will cause it to return to normal behavior. Well, nothing except if I use the magic trackpad, which just instantly makes it normal—but the problem happens even if the trackpad doesn't have batteries.

What can I do to either prevent this from happening or, preferably, to reset the cursor?

 

[satcomer]

Lean to use Activity Viewer to find/stop any miss behaving programs.