Thanks. I have reread the old thread, and it must be connected with scrolling with other programs. But I do not know if it is TW Logos, TW Folio or Bart. I had all of those open. It is too late for me to send a problem report, but if it happens again, I¨ll try to do that and make a note of which programs are open and how they have been set to scroll together. I guess there is only a problem if one of those programs send references to PT8. I think I had BART both sending and receiving for a short while, but Logos was also set to scroll in the A group. I thought it was fixed, and I have not had the problem for months until today. My best guess is to test with BART.