Probably has a broken trigger return spring. I think S&Ws just have a V spring in there. I've replaced these on H&Rs and other old topbreaks.
Wolff has packs of V-springs that take some fitting but I've been able to use them with some success:

https://www.gunsprings.com/GUNSMITH%.../mID132/dID388

https://www.gunsprings.com/GUNSMITH%.../mID132/dID389