I had in mind that this Chord Overlapping Mode would be the default mode.
In addition to this mode there would be two other modes:
 - Solo Mode (no chords at all) instead of chord overlapping mode;
this was the earlier mode, and
 - Chord Mode (do not proceed in time at all); as it also was previously.

I am going to implement these to the NotationView and MatrixView soon.
Current implementation is still a bit preliminary.