Auto refresh while changing pos.x of seleted note

Hello,
I try write plugin that can change space between selected notes (chords) for Liturgical Eastern Music, something like (edited in MuseScore):

I write code for fixed space, and it work. But I think also about some gui-control for changing this space on the fly like from Inspector. Now my second code make all changes, but apply it only AFTER gui-control closed. Can I do this without closing control's window?