My apologies if this is covered somewhere else, or if it's already been covered here (I have had a look/search but couldn't see it anywhere). Not a single video (either here in the Saxxy's or trailers for games etc) will go fullscreen when I click the fullscreenify button...fed up of having to do it through a web browser. Any ideas? (Obviously it's fine in a web browser, but, I'd prefer to do it through Steam...)

Cheers!