How to get back to full screen?

Occasionally I'll be watching something I've recorded and want to check either the program guide or the list of recordings. If I have moved around the menu system a lot, I can't get my recording back to full screen. Hitting the back button doesn't work. I have to pull up my recording list, select what I am already watching and resume to get back to full screen.

Is there a trick I'm not aware off? Or is this just the way it is?