Revealing mistake: In the scene where Ashley is brought back wounded from the raid where Scarlett's husband Mr Kennedy was killed, Melanie grabs a gas lamp to follow the man carrying Ashley to the bedroom and you can see an electrical cord hanging down from it.
Revealing mistake: When Scarlett finds Twelve Oaks completely destroyed, the carriage in the background is not real. As Scarlett walks toward the staircase, both the carriage and Prissy are not real, it is just a picture that has been painted to make it look like they are sitting there.
Revealing mistake: After Frank Kennedy's death Scarlett is sitting in her room, "mourning" and drinking. When she hears Rhett's carriage she goes to the window. In this moment you see shadows, either from crew members or equipment, cast through the room, especially visible on the bottle on the table. There is also some funny shift of the backdrop outside the window.
Revealing mistake: There is a very short scene in the second half of the film where Mrs Meade and Dolly Merriweather are sitting at a tea table gossiping about Scarlett's behaviour. There is a teapot in the middle of the table, and Dolly Merriweather is sitting behind it. Yet the teapot is casting a shadow on the wall and Mrs. Merriweather isn't.
Revealing mistake: When Rhett picks up newborn Bonnie from her bassinet, you can see that he picks up a doll, not a real baby.
Revealing mistake: If you look closely at the lily Scarlett is holding in the very first scene of the film, you can see that it's artificial.