PS: There seems to be a bug on my machine. When I press the Play button in the Library, the song screen opens, but the previous song performance is still open there and nothing happens. I have to press the "in Apple Music" in the library; then it switches to Apple Music, where I press Play again and switch back to OnKey. Can't OnKey start playback on its own?

Thanks, taking a look now, I'm seeing a few weird things myself here. I'll try to make this smoother and push a new release. Switching from songs loaded in Apple Music to songs loaded in Spotify doesn't work too well at the moment.