The TV-like machine on which Leslie Quayle is shown performing "The Man with the Big Sombrero" is a "Panoram," a video jukebox that showed short films of popular bands and entertainers during the 1940's. The films shown on it were called "Soundies" and were essentially the music videos of the time.
At the time she made this film, Pola Negri, who had been a major star during the silent era, hadn't been on USA screens in a decade because of her work and association with the Nazi film industry in Germany. This film didn't exactly revive her career - after making this movie, she only appeared in one more film, As Fiandeiras da Lua (1964).
"The Screen Guild Theater" broadcast a 30 minute radio adaptation of the movie on October 4, 1943 with Martha Scott and Dennis O'Keefe reprising their film roles.
June Havoc is Gypsy Rose Lee's sister. She was known in vaudeville as Baby June, according to Em Busca de um Sonho (1962).