Continuity mistake: Stuart has pictures from the ball at Leopold's that show Kate standing at the back of the room looking in the room. At the end of the movie, you can see the set up for that picture. However, for Stuart to have *taken* that picture, he would have to have been standing on the platform with Leopold to take the picture, but he's not there.
Continuity mistake: During the dinner scene with Kate, Leopold and Charlie, Kate gets up and starts picking up her plate and the ketchup bottle. The shot changes to Leopold starting to stand up, then it switches back to Kate who is picking up her glass of wine instead.
Continuity mistake: When Hector the kid offers Leopold some Pirates Booty - Bart the dog has changed positions on the couch.
Continuity mistake: In the apartment scene where Kate is wearing a light blue turtleneck sweater and fighting with Leopold, her collar is up in one shot and is folded over neatly in the next.
Continuity mistake: Near the end when Kate is in her hall gown, her dress bodice is plain and the skirt comes to her ankles. When she stumbles in to Leopold's party, her bodice now has short black lace and her skirt has a train and a bustle.
