Audio problem: In the close-up, as Jack is whistling "Toot-Toot-Tootsie," it doesn't match up with his mouth.
Continuity mistake: Jack is finished singing Toot-Toot Tootsie and the audience is applauding. The guy sitting to the viewers left, with no cut-aways suddenly has a cigar appear in his mouth, he removes it then its back in his mouth.