as penDown. Idea is to be able to set timers to get bonus square
hints etc. without stylus. Works, but transitions are rough because
keyDown doesn't know whether keyUp will result in a focus change.
not dived and tray or scoreboard focussed. This lets platform decide
to display top-level focus via mods to all elements. Second, when
moving focus to top level from dived, claim not to have handled the
key event (but return true if needs redraw). This allows platform to
handle shifting focus without requiring callback (which removed.)
