#1671 When Merge File dialog is canceled, MIDI output port is deleted

[musewhirl]

Canceling Merge File dialog results in a deleted MIDI output port. Steps to reproduce in a freshly installed RG v23.12:

1. Open Manage MIDI Devices and ensure that the MIDI has an output port
2. Select File/Merge MusicXML File (s)...
3. A Select Files dialog opens (NB: canceling at this point has no observable issues)
4. Select a MusicXML file
5. A Merge File dialog opens providing some merge options
6. Click Cancel
7. Open Manage MIDI Devices and the MIDI now has no output port i.e. at least one side-effect is observed

Undo is unaware that anything has changed and closing the session results in the side-effect no being saved. However, if user had already changed something in that session and/or continued in that session after the cancel and then saved, the deleted port would probably have been saved along with it (I didn't try that though).

Workaround is simple...just select the port again when you realize there is no MIDI sound from any of the tracks related to that MIDI device...the named device was still attached and all instrument parameters will probably be unaffected.

[Philip Leishman]

It seems the merge of MusicXML files was not respecting the permanent flag.
I have corrected this.
Please merge

[Ted Felix]

Merged as [aecdc1]. Please test latest git.

[musewhirl]

I tested this in master [d0760d], and it works fine now.