In this example, the publisher I work for is requesting an extender line as indicated in red.
I posted this on Music Engraving Tips, and the overwhelming consensus was that such extenders were absolutely necessary. I do know several of the people who commented are choral music veterans or established composers, FWIW.
It’s extremely difficult in Dorico at present. I’ve tried changing it to two tied quarters, redoing the lyric, and fiddling with the extender, but the extender line jumps around randomly when I try to edit an extender line that Dorico knows is no longer “correct” (since the note has been returned to a half note).
I’ve also tried using the bottom staff and setting to “above,” but this is a nightmare for casting off, and forces me to change the staff spacing.
I’m requesting (pretty please) an option to select the syllable and turn on a “lyric extender” property from the bottom panel.