The writing credit card originally read: Screen Play by Harry Clork, and the smudged out credit read: Suggested by the play "No, No, Nanette," by Frank Mandel, Otto Harbach, Vincent Youmans and Emil Nyitray.
Notably missing is the name of lyricist Irving Caesar, who was a co-lyricist of the original Broadway score of "No, No, Nanette." Yet receiving credit are Frank Mandel and Emil Nyitray, who actually wrote the play "My Lady Friends," on which the libretto of "Nanette" was based.
Apparently, there was a subsequent dispute involving these credits, the details of which remain obscure, but as part of the settlement of the matter, Warners agreed to blur the source credits on all future prints of the film (which now includes video, DVD, Blu-ray and cable TV versions).
On the DVD release and Turner Classic Movies showings, beneath the credit "Screen Play by Harry Clork" the credit for the play "No, No, Nanette" and its writers as source material is obscured by a reddish-brown smudge. Furthermore, lyricist Irving Caesar was omitted.