Musocity, thanks.
Yes, the "copy the midi to another track." that is what I been tinkering with, and I agree on "It needs a better way".

P.S. Muting audio is not the best option, as it will silently redraw RT each change/regen. Some sort of one click combination Freeze+Mute audio should solve it. Toggling back, could regenerate RT to accept all new changes on next playback.