Edit Drumset: Allow instrument names to be saved even if "Notehead" is set to "Invalid"

MS 2.1/ Win 7/10

1. Create a Drumset in the New Score Wizard.
2. Go into note input mode and click on the "Edit Drumset" button.
3. Click on the blank space at MIDI note 39.
4. Enter "Hand Clap" in the "Name" field.
5. Click on the "Save as" button and save the .drm file.
6. Exit the "Edit Drumset" dialog and come back to it. Notice that "Hand Clap" is still there.
7. Click "Load" and load the saved .drm file.

Expected result: Handclap is saved.
Actual result: Handclap is missing. It seems that Instrument names cannot be saved if the "Notehead" is set to "Invalid".

Feature request: Allow instrument names to be saved when the "Notehead" is set to "Invalid." This will allow a .drm file to contain a complete GM2 MIDI map which can be used by the user as a handy reference tool. The instrument names without valid noteheads do not appear in the Drum Input palette.