I'm an occasional user of X-Plane 10 on the Mac. When I first had this problem several months ago after an update (don't remember which one - been using X-Plane since 9.2? and 10 since release), i figured it would be fixed in the next patch, but the problem continues. In every plane I try now, when I click on something to change GPS, Bug, Autopilot altitude, etc. I click once, but it sticks and instead of moving one increment runs at full speed for anywhere from a half second to several seconds before stopping. It makes it impossible to accurately change any settings in the cockpit. It happens in 32 bit and 64 bit. All planes. Mac Pro Quad core 2.66 32 Gigs of Ram ATI Radeon 7950 (also did it on Radeon 4870) OS X 10.8.4 (Also did it on 10.7.5) Any ideas what might be causing this? Rich Quindry