Tick in a Text causes an internal error

(Bug, Closed -> Misunderstanding, Priority: High, Test Status: No automated tests yet , Reported By Justin du Coeur, )
Editor
Summary: When entering [this song]() into my Songbook, I tried to enter the name "Arthur O'Shaughnessy" in the Created By field. This crashed, with some sort of internal error.
Never mind. This Created By field is a tag, and moreover turns out to be an old Tag Set by mistake. So this error is not surprising, and should go away as the old Tag Set gets deprecated and removed.