Instrument remains in midi file after changing to another instrument
1) create a score with two instruments: piano(G clef), soprano
2) press "i" and change soprano to another instrument, say, ukulele
3)export the midi file
4) We can find three tracks: piano, soprano, ukulele. But soprano is not what we need actually.
I uploaded a template that contains 5 staff ( 5 instruments). However, when I export a midi file, there are 8 tracks( include some instruments I have replaced with)