Just installed the latest update and noticed a slight problem.

When it opened after update I had a large top to bottom white pane marked 'Play To' on the extreme left.

Clicking the x top right wouldn't remove it but got rid eventually from within 'View'

Now when I stop and restart Mezzmo there's a Library pane covering two thirds of the screen, I can shrink this in the usual way but it doesn't stick and returns on a restart.