Manytimes you want to delete or change an instrument in an old song you are editing (to save memory) but you are not sure if it is used in the song, perhaps on some muted track.
In 99% of the case I cant use the delete unused instruments, since there are often a couple of unused instruments I dont want to delete.
Therefor it would be very useful with some information displayed if an instrument is used in a song.
Perhaps a Mute icon, so that you can also mute the instrument.
This will only appear if the instrument is used in a song.
Then we save space (only one icon) and we know the instrument is used.
It would also be nice if the instrument and or the icon next to it would flash while its playing in the song.
Making it easy to see what drums are playing etc.