Romberg was Hungarian, not Viennese.
When Ann Miller is singing "It", she takes off her beads and drops them over the head of a male dancer dressed in a yellow sou'wester coat. Immediately after she gives a little scream, the beads have vanished, never to return.
Songs are not presented in the correct chronological order in which they were written, nor from the shows in which they were introduced. For example, "Maytime" was a 1917 show, not a 1920s show, as presented here. "Softly, as In a Morning Sunrise" came from "New Moon" (1928) and was not written a decade earlier for Gaby Deslys; "It" was from "The Desert Song" (1926), a much later show than "Artists and Models", as presented here.
'Frau Mueller' (portrayed by Helen Traubel) is a fictional character created by MGM writers, and bears no resemblance to any real person with whom Romberg was ever involved; Romberg's Manager, Townsend, portrayed by Paul Stewart, and two associates, Judson and Butterfield, portrayed by Jim Backus and Douglas Fowley are also fictional, as also is the show they are supposedly writing, referred to as "Jazzadoo".
No mention is made of Romberg's first marriage.