If you’ve got four-finger swipe down set to App Exposé on your Magic Trackpad or MacBook’s trackpad like I do, hover over a dock icon of a running app and swipe.

I have no idea if this is new for Lion or not, but what basically happens is you enter App Exposé for the app in question without having to switch to the app first.

This behaviour was present in Snow Leopard (dubbed “Dock Exposé”), and was invoked by clicking and holding on a running app’s dock icon. I’m unable to click and hold for Dock Exposé in Lion (doing so brings up the right-click contextual menu), so I can only assume this new hover-over method has replaced it.

As I said: no idea if this is a new addition for Lion, so do let me know if I’m off my rocker.

UPDATE: The trusty Michael Norton has informed me that he’s able to click and hold for Dock Exposé on his Lion install. Sadly, that’s not working on my end.