Hi there. Thanks so much for trying to help me (I'm just going nuts with this, and appreciate any input!). But "Por una Cabeza" isn't the one, that's from the film's opening. This scene is about 30 minutes into the film, maybe a bit more, and is definitely a waltz, not a tango. It sounds like Strauss, but a rep from the Strauss Society of Vienna assures me that it isn't, it's something much more current, perhaps even post-war. I've found just about every other uncredited piece from the film, including "Love Will Forgive You," "Meinen Lippensie Kussen so Heir," "Tango Jalousie," "Bourree, from English Suite #2," "Gloomy Sunday," "Erika," "Mamatschi," "Gute Nacht Mutter," "Die Halzauktion," "La Capricieuse Opus 17," "Happy Wanderer," and "God Bless the Child," but this one remains elusive.