Opening and closing a lot of full-screen apps in Lion? Expect to...

Opening and closing a lot of full-screen apps in Lion? Expect to run into this quite a lot. I'm calling it the linen abyss. It's what's behind that full screen app. You'd think it would just disappear after the app closes, but sometimes it just doesn't, leaving you there to stare into its infinite linenness (liniverse?) until you swipe away.