Ok. I have done a complete factory reset. Loaded a SGU file from the BIAB user's group, using the Sinatra MIDI style, with no events other than notes and sustains in the event list. Loaded the VSTSynthfont 64 synthesizer as default. Hit play and adjusted my mix. Hit play again and the levels jumped up. Tried adjusting individual tracks, and as I moved them just slightly, the level on that track jumped down. This kind of thing has been typical when using the default synthesizer. If I put a separate synth on individual tracks, they stay put. Sorry, I haven't gotten back to this sooner, been pretty tied up last few days.