Since deletion in the instrument list works for multiple entries / selection, it would be maybe a bit more practical, if the “delete unused instruments” function would be changed into “select unused instruments”. Then you could deselect some instruments you maybe want to use later…
BUMP 
Sometimes you want to delete unused instruments, but at the same time still keep some YET not used instruments. So if the function only was highlighting unused instruments instead immediately removing it, it would be more flexible. And then additionally pressing delete is not very inconvenient.
2 Likes