Corrected entry: The drainpipe running down the building where the Thorvalds live, the one between the living room windows and the bedroom windows of the block, becomes at least 1 foot (10cms) wide at least three times through the film, and changes to a gingery colour, almost as if it has become a plank of wood standing against the wall. It also has a pipe or something running into it in a couple of shots, just above the Thorvalds' bedroom window, but as this would be the "dog" couple's bedroom, there shouldn't be a pipe coming down from there. At other times the drainpipe just looks like an ordinary drain pipe. Even though we are not meant to be looking at anything but the activities through the windows, the drainpipe is very evident in many shots as the action frequently moves over it into the adjacent rooms. (Visible in the remastered video version and others.)
Corrected entry: Jimmy Stewart has a broken leg in the movie. However, the cast shifts from one leg to another.