Theme change clears "notes"
Changing something on a song in the schedule should not change the notes unless you're editing the song in the database and applying those changes to the scheduled song. Since there are no notes on the song in the database, if you make changes to the database song and apply those to the scheduled song, it will overwrite the scheduled song with whatever is in the database.
But, if you just edit the song in the schedule, it will not remove the notes. If you're wanting to change the theme on the scheduled song, the easiest way to do that is to go to the Themes tab and drag and drop a new theme onto the song in the schedule. If you need to make lyric changes to the song in the schedule, right click the song in the schedule and edit there instead of in the database and that will keep the notes.
It's not a bug. If you replace something in the schedule from what's in the database, it's going to overwrite what you have in the schedule. You're basically telling it to delete the schedule item and add it back in from the database with the changes.
I would recommend when you're editing, edit the item in the schedule. If you need to save it to the database, you can do a check for changes and update the database from the schedule.
You can definitely add that as a feature request to maintain the notes in the schedule when updating the same item from the database.
I did some more research, and you are correct: dragging a theme onto a schedule item does NOT remove the notes. I was sure it did so it must be something else the volunteers are doing. More research will be required.
So if I edit the item in the schedule rather than the database (which should keep the notes intact), then do a [check for changes], I can update the database without disturbing the schedule item? Or would it still remove the notes at that point, requiring I wait until the service is over to check for changes?
As for the feature request, I may do that. As I stated earlier, It makes sense to me that schedule notes should never be dictated by database changes, especially since they can't be edited by the database. If notes were saveable though, that would probably be even better. Then things like slide order would be persistent and easily visible.
If you check for changes and save the scheduled item to the database, it will not affect the schedule at all and the notes will stay intact.