There is only one reason I can think of why we should keep the promo popup,
and that is that blind people cannot use the new mechanism because they
cannot use a mouse.
But it is actually a bad reason, as there currently is no special XBoard
version for the blind
as there is for WinBoard. And to handle the promo popup through key-strokes
+ audio feedback
is actually more cumbersome than typing the move using auto-popup of the
move type-in dialog.
So my guess is that even blind people would not miss the promo-popup very much.
