I just found that green keys can be also used for chords, not just for single notes
And even wrong “chords” work, i.e. you can click 2-3 keys together randomly, and they sound as a real correct chord
This way, the “sound” improves a lot
Try and let me know
Ah right, your headline said “keys-lock” indeed, my bad.
I guess I assumed that was their intention in the first place, that you can play random notes/chords, and they will always match the selected chord (or alternatively scale)