I finally realized I'm doing players and instruments all wrong. I'm engraving movements from Pierrot, and had a separate player for flute and piccolo, violin and viola and the clarinets. So I went into setup, selected the piccolo and clicked 'move to player -> flute'. Nothing happened. I went to the flute player card and right-clicked, and the piccolo appeared. All good. However, Dorico then went unresponsive. It didn't crash, but it wouldn't respond to any command - save, write mode, quit, or other attempts to move instruments. The menus all opened and flashed when I clicked on them, but didn't actually do anything. I restarted and tried again, this time moving viola to violin. Same results. I tried creating a new flow with all players selected, but that didn't help. I've restarted several times, but can never get this to work. Has anyone experienced this?