I know I saw The Mystery of Edwin Drood during its original Broadway run, back in the mid-1980s. But darned if I can remember it. That is probably the most telling thing to say about the musical, which has been revived in a lively, very polished but ultimately disposable production directed by Scott Ellis. Conceived and written (music, lyrics and book) by Rupert Holmes, it’s based on Charles Dickens’ last unfinished novel, staged as a play-within-a-play being performed by a Victorian acting troupe. The tongue-in-cheek shenanigans are often fun, the actors are pros (among them Broadway legend Chita Rivera), and Holmes’ score is a marvel, old-fashioned yet totally distinctive, with a big upbeat number, “Don’t Quit While You’re Ahead,” that is the English music-hall answer to “One” from A Chorus Line. But the audience-participation gimmick is a bummer. When Dickens’ story stops cold, the audience is asked to vote on the ending — which the cast then performs to order. I can’t think of a surer way to reduce an evening of theater to utter trivia.