Right now I have 3 different machines with Lion on them, and this is happeneing on all 3. I have 3 finger swipe to navigate enabled. It works fine in everything except Finder. Well, that is to say, it EVENTUALLY works in Finder. If I open a new Finder window, double-click on a folder and then try to swipe back, nothing happens. I try it again, nothing happens. I let it sit for a minute or two, and try again. Then it works. If I close that Finder window and open a new one, same thing happens. It'll also randomly stop working within the same Finder window. I do not have the issue in any other apps. Anyone else seeing this? Kind of annoying but haven't been able to find a fix as of yet.