Comment 2 for bug 609927

Fixed at lp:mixxx/1.9 r2639

I ended up just hiding the window, opening a dialog of some sort was turning into a total pain (can't create a dialog in a hung GUI...). Only solution would be to move destruction of MixxxApp to a different thread and that's a can of worms I'm not willing to open at the moment over a relatively rare/minor bug.