I've had my 2012 MBA for a bit over a month and recently the three and four finger trackpad gestures have randomly stopped working (two finger scrolling still works). The only solution I've found is to open up terminal and type in "killall Dock". However that only temporarily fixes the problem as it comes back later. I have all updates installed and I've already tried reinstalling OSX to stock without restoring from a Time Machine backup. I've made a Genius Bar appointment for tomorrow, but I figured I'd ask around here.