[GraemeJ]

Thanks for explaining that Andy.

I've had a play with it and concur that it is does not do what one expects.
1) Display a set list and choose a song
.
.
.
5) Choose collection containing the song.
6) Select song and enter "edit" mode - the note is missing
7) Reselect song via the set list and it is present.

I don't ever get the note being displayed (although I do get a note displayed on another song that I set up a long time ago)

I think this is because you added the note to a chart as 'setlist note' - which is the default option.  Had you changed it to a 'song note' before closing the edit window it would appear every time you opened the chart from within the 'collection' or any other tab. As you have it, it will only show in that setlist.  The default mode makes a lot of sense, as you could well have the same song in different setlists, which require a different note as to how it's played - I know I have charts like this.

My original comment was the way that the action of changing an existing note from 'setlist' to 'song' (and visa versa) was confusing in its result.