[Feature] Enhance “mew” numerical input

Hi all, @ksooo,

the new numerical channel number input is quite nice and usable. Thanks a lot… however, I think it can be further improved.

1. pressing OK/select should immediately confirm the numerical imput. Currentyl the event is sent to the active window, which can be quite confusing.

2. pressong 0/zero should trigger the action immediately- Leading zeros do not make sense, instead the zero typically switches back to the previous channel.

Thanks
Diddle.