After exporting XML, the document is marked as modified and wants to be saved again when you close it.
I remember Finale always drove me crazy in this regard… open a file, stare at it for a second, and try to close it. Warning! Gotta save!
Dorico does have to perform some edits on the project in order to export the MusicXML (e.g. it has to ensure every layout is set to display transposed pitch rather than sounding pitch), and it automatically undoes them again, but this leaves the project dirty. I’m not sure if it’s feasible for us to prevent these operations from marking the score dirty, but we’ll take a look.
The problem has only been around since v3.1.
Creating a PDF, XML, MIDI, or audio should not modify the file.
Perhaps one should distinguish the dirty-flags, whether they were set by Dorico or by user (edit and change the data).
The “normal” state is, if I haven’t changed anything, I don’t want to save (read-only file/archive).
I hope the team will find a good solution.
Yes, we made a number of improvements to MusicXML export in Dorico 3.1 that necessitate the edits that I’m talking about, which is why the behaviour is different in the new update.