You know, I think you're right. As I have a pre programmed hotkey on my keyboard for bringing up my music app, which I never noticed before really until looking now.
It's somewhat inline with my close bracket key too. It's funny how it doesn't bring it up with just the bracket key though...
edit: I'm actually able to make it come on now, holding shift down pressing ":" and then pressing ")" it pops up every time i do it now, it's when shift and ":" is held at the same time and then pressing the bracket key. It's very weird, even though it is a hardware fault.