A bit of work towards getting editors closing nicely with the application.  Now it hangs on the sequencer background thread, waiting for it to close; so it's not solved for now, but it's progress.
Selecting an element should make that row active.
Fix fps display.
Combine parallel intents on discrete elements by color in a highest value wins.
Reset element states in a common place so all sequence end events reset the states. Solves a bug where autoplay of a small section left the element states hung.