Continuity mistake: When Dorothy slaps Lion on the nose for chasing Toto and shouts, "Shame on you!" in the wide shot, we see Dorothy's right arm with no mark on her skin. It then cuts to the medium shots, and there's an inexplicable long, thin blue mark (it's not a loose thread) on Dorothy's arm near her elbow, while she's holding Toto. This blue mark vanishes in the wide shot when she puts Toto down, and Lion begins to sing. (00:50:25)
Continuity mistake: During the Blue Birds in the Moonlight song you can see Gulliver holding his drink. In the next shot while he's laughing the drink has disappeared.
Continuity mistake: When Casper strikes the picture of Daffy Duck on the stone, the impact makes Casper dizzy and he drops his club in the process. But when Casper walks past the stone to hunt the duck that Daffy promised him, there is now no sign of the club.
Continuity mistake: When the dog in the audience has his feet crushed by the hippopotamus sitting down on his chair, you can see that there is an empty chair next to the dog, but in the next shot the chair has disappeared.