Hey @Basstor,
This has actually come up before from other users (check footnotes below), so it’s on the radar as a feature request. As of now, AbleSet just doesn’t work that way, and supporting true duplicates would mean rewriting some core parts of how the setlist works from the ground up.
Right now, to get a song to show up multiple times, you’ve got two options depending on your setup:
Single-project setup
Duplicate the song’s region on your Ableton timeline so it has two separate locators (e.g. Prosit and Prosit (Reprise)). Each locator counts as its own song, so both show up as separate entries and you can place them anywhere in the setlist.
Multi-File Project setup
Keep two copies of the song file in your project folder. Each file is its own entry, so you can drop it into the setlist as many times as you have copies.
On the warning idea (“this song already exists, add anyway?”), that’s a good UX suggestion, I’ll pass it along together with the broader “add song twice” request.
Hope that helps!
[1]Add same song twice in a set - #2 by leolabs
[2]Duplicate Song In Setlist