This is a confusing bug. It appears that the app has quit, but music still plays & it is not obvious how to do anything about it.
I have learned now that you can right click the icon IF you have it in the dock, but why does the icon not show the app running? - without a dot under the icon it looks like the app has correctly quit, but it has not. This is a different behaviour from every other app.
Suggestions: Quit the app completely when you click X. or show the dot on the dock icon if the app is still running.
This is a confusing bug. It appears that the app has quit, but music still plays & it is not obvious how to do anything about it.
I have learned now that you can right click the icon IF you have it in the dock, but why does the icon not show the app running? - without a dot under the icon it looks like the app has correctly quit, but it has not. This is a different behaviour from every other app.
Suggestions: Quit the app completely when you click X. or show the dot on the dock icon if the app is still running.