The key-click volume setting works now. It was asking the platform to
play its own keypress sound at a given volume, and plenty of devices -
Samsung's among them - ignore that volume and use the system's touch
sound level instead, so the slider appeared to do nothing. The click is
the keyboard's own sample now, played by the keyboard, so the number
you set is the volume you get. Turning it to zero still silences it.
