Continuity mistake: When JB talks to Ms. Jones on the intercom after talking to his wife on the telephone, he asks where the "You know" is. She says "It's in your top right-hand drawer." You can see him moving to his left.
Continuity mistake: When Finch first gets the job at World Wide Wickets, he asks Bratt to light his cigar. The shot then changes to Rosemary and her friends, and when it comes back to Finch, the cigar has disappeared.
Suggested correction: Actually, no! His left hand is not in frame anymore, but he is looking at it with a "What am I gonna do with this thing?" expression. And even after a long while and a lengthy cut to the president's nephew, at the very end of the scene when Finch says bye to Rosemary and her friends, he's specifically shown holding the cigar as he flips through his book.