"Henry Fonda immediately complained to Sidney Lumet about the cheap backdrops outside the jury room windows when he walked on set. "Hitch had great backdrops, you could walk right in them," said Fonda, referring to the previous film he made with Alfred Hitchcock, The Wrong Man (1956). Lumet assured him that director of photography Boris Kaufman had a plan to make them work." From IMDB
From my chair, the nondescript backdrop keeps my focus on the drama inside the jury room.