Crash when trying to add Media player by Index binding in Background Rack

Tags: #<Tag:0x00007f97877b9780> #<Tag:0x00007f97877b96b8> #<Tag:0x00007f97877b95f0>

In the Background Rack.

Add a binding for
‘Media Player by Index’, ‘Is playing’
to
‘Media Player by Index’ ‘Color’ (sic)

Cantabile either crashes immediately, or crashes when I try to make the Media Player play.