After Diane insists on paying for dinner, Frank declines her offer, noting that he can afford it even on his salary. He takes out his wallet and places money on the table. Diane then later says, "At least let me pay for my half." He obliges. She takes out her purse and gives him some cash. Frank then picks up the money he had put down (which would have covered the full bill), puts her money (covering half the bill) down in its place, and gives her all of his money, which she puts in her purse. Nobody ends up paying for Frank's half and Diane ends up with more money than she started with.
When the juror requests to ask a question of the prosecutor's expert witness, the defense attorney gives his permission, not once but twice. Proper procedure would be for the juror to make his request of the judge -- who's in charge of the trial -- and for the judge to give his permission.
While the chessboard is set up correctly in the game between Diane and her father, with a white square at lower right of each player, it is set up with a black square at lower right when Diane looks at the board at the end of the movie.
(at around 2 mins) The shadow of the microphone at the top of the headboard is visible, right after Mrs. Tremayne says "Someone tried to murder me." Then the microphone (shadow) turns to the left towards another actor.
Defense attorney Fred Barrett at times slips into an accent -- southern or New England -- but at other times has no accent.