Thanks Noel. Yes, a midi style is loaded. One of the original ZZ.... styles in a new song ie. blank chord sheet except for a C on the first beat. (I keep RT style autoreplacement of MIDI styles switched off.)

I just tried it again, the sequence I described above 10 times in a row. It worked properly on the third, fifth, eighth, and ninth tries. On the others, the GM2 patch assignment screen did not pop up. Nothing at all happens. I repeated the expt. and got normal behavior six out of ten times. Seems that it works randomly.

If you use a GM2 softsynth with the 2017.454 update, do you not see this?

Thanks, Ron