Continuity mistake: When Jimmy Stewart is talking to his girlfriend, he gives her a flower, and at different points in the conversation, she has it over her shoulder, or on her lap, depending on the angle of the shot.
Continuity mistake: When Daffy walks to the door of the film library, the door is green. When he opens the door in the next shot, the door is grey.
Continuity mistake: When the St Bernard dog is preparing the drink for the frozen bird, he puts a cocktail stick with a piece of orange and a cherry into the glass, but when we see the dog holding the glass in the next shot, the cocktail stick has disappeared.
Continuity mistake: A sow is nursing four little pigs. When the farmer brings food, she rises and walks away, leaving behind five little pigs.