"Leise, ganz leise . . . ", waltz duet No. 7 from the operetta "Ein Walzertraum" ("A Waltz Dream") "Leise, ganz leise . . . ", waltz duet No. 7 from the operetta "Ein Walzertraum" ("A Waltz Dream") Main opus "Ein Walzertraum" ("A Waltz Dream"), Operetta in three acts