I just checked mine and the vibrate still functions when the screen is locked. I didn't try the correction buttons.Thanks for the feedback. I’ll take another look at locking the hand held unit.
Weimdogman is right. If you are running more than one dog you can't switch dogs on the handheld if the screen is locked. The Alpha 100 is certainly not user friendly. I'd upgrade mine but my hunting years are numbered so I'll put up with it until I quite hunting. Both me and my dog are getting old and hunting is getting tougher each year.