Hi guys. I'm having an annoying problem here. Once in a while, when I start Spotify (linux version) a blank window appears in foreground. I can't select, close or move this window and I have to close my session or restart my computer in order to get rid of this annoying window.
I have Linux Mint 14, 32bits. with Cinnamon desktop.
Thanks for the attention.
EDIT: An image of what I mean.