I've seen an issue like that in the past with e-ink devices where the device basically goes into a sleep mode of sorts if the user hasn't touched the screen for a certain period of time, causing it not to redraw the screen or respond to things like pedal presses. However, I haven't heard of that happening with a standard tablet, so I have no idea if something like that is related here, but it doesn't sound like there is much time between when you triggered the facial gestures and when you've touched the screen, so that's probably not the issue. This could be a tricky issue to track down unless I can reproduce it myself. Has anyone else encountered this?
Mike
Mike