Though Ziegfeld anticipated opening his new theatre on Sixth Avenue with "Show Boat", the epic nature of the work required an unusually long gestation period and extensive changes during out-of-town tryouts. Impatient with Kern and Hammerstein and worried about the serious tone of the musical (he strongly disliked the songs "Ol' Man River" and "Mis'ry's Comin' Aroun"), Ziegfeld decided to open his theatre in February 1927 with "Rio Rita", a musical by Kern's collaborator Guy Bolton. When "Rio Rita" proved to be a success, "Show Boat"'s Broadway opening was delayed until "Rita" could be moved to another theatre.