Who was the pianist?
IMDB gives no info on the pianist in the concert scene, although some "Piano Concert Extras" are listed. Anyone have any ideas who the performer was? He was clearly an actual concert pianist, clearly actually playing - even playing a few live "clams" - at what apparently was an actual concert.
In the following scene, the characters mention "de Pachmann" (but he died in 1933). Then they hint at the piece he was playing ("Didn't you like the polka?" "I think Shostakovich is so exciting") - at least giving the composer a mention, if not the pianist.
I also thought such a wonderfully goofy piece of music (the polka from Shostakovich's ballet "The Golden Age") was a clever choice to accompany the intrigue going on in the audience.