MIDI - Mixer changes channel mapping for export

• Jan 21, 2019 - 09:03
Reported version
3.0
Type
Functional
Frequency
Few
Severity
S3 - Major
Reproducibility
Always
Status
active
Regression
No
Workaround
No
Project
MuseScore
  1. Create a Score - Score.mscz - 2 piano and 2 drumset staffs.
  2. Export to MIDI - Midi1.mid
  3. Open Mixer w. no further action
  4. Export to MIDI - Midi2.mid
  5. Select last drumset in Mixer (staff 4)
  6. Export to MIDI - Midi3.mid
  7. Select the other drumset in Mixer (staff 3)
  8. Export to MIDI - Midi4.mid

Result;
MIDI1 and MIDI2 are correct.
Import1.png
MIDI3 the last staff has changed from Drumset to Piano
MIDI4 both drumsets has changed to Piano
Import4.png

Conclusion:
When the percussion/drumset staff is selected in the Mixer the assigned MIDI channnel is changed, causing export to MIDI file to have the instruments wrong.

See also:
https://musescore.org/en/node/281682
https://musescore.org/en/node/282062