In the scene where Nat Moyer (Walter Matthau) says to Midge Carter (Ossie Davis), "My God, you're black!" He stands up and puts on some black glasses. When the two start laughing, Nat takes his glasses off and sits back down. When the camera is then on Carter, it shows the back of Nat's head and the glasses are back on his face.
While Moyer arrives with a briefcase to the meeting with Carter and Danforth, he leaves without it.