Touch was controlling another player.
Music was playing, Now Playing screen was displayed.

In SBS WebUI, I cleared the current playlist.
Music stopped, the playlist was cleared.
Touch displayed a message indicating that the playlist was empty.

However, I could not get out of this screen.  i.e. back button doesn't work, etc.

If I start new music via the WebUI, the current playlist screen displays the new music, but still can't get off the screen by clicking anything.

I have got into this state several times now; so it is repeatable.