Oh! That's a shame, I quite liked that bug! Thanks anyway.
It is expected behaviour for the previous track to continue playing when you click play on the next one. You must eject the previous track if you want it to stop early.
I believe there was a bug in a previous version where the previous track would stop when the next track was played, but this was not intended behaviour.
So I have the programme set to Live Assist mode, with the segues set to "next" instead of "stop" - but when I press play on the next track, the previous one continues playing until I manually eject it. It never used to do this, so I don't know what's changed to make it start. Any ideas on how to stop it doing that?