Just fc'ed twice on chrome trying to post this, could have been a phantom back press. Was closing the keyboard randomly and other odd stuff. Turned off, cleaned screen, rebooted, crossed fingers, typing (uncrossed). Better, if it recurs I'll find an Ouija board app before attempting full exorcism. Bjs- careful cleaning around the crack, some cleaners may contain water, which could short the grid. A screen protector may be a good idea.