Continuity mistake: The Lion sees a cat in his orchestra sleeping and looks to the right of his podium (from his perspective). But moments later when the view switches to behind the lion, he is looking at the cat to the left of his podium. (00:04:35)
Continuity mistake: When Goofy searches through the dresser drawers one of the ghosts causes trouble, then Goofy breaks through the top of the dresser and winds up trapped inside, but when all four ghosts appear the dresser top is perfectly fine and that damage has vanished. Also, two of the drawers (one large and one small) fall out of the dresser, but as the four ghosts are pushing the dresser those two drawers have reappeared in their proper places.