When Pima trips while running away from the Jabberwocky, a close-up shows her foot tripping over a rock lying on grass despite her running on concrete.
When in the studio scenes, in all the shots facing the door, the several crew members feet are clearly visible in the top left hand corner.
Throughout the movie characters make reference to the "Red Queen" when they are talking about the Queen Of Hearts. They also talk about the Jabberwocky as though it is a character in the Alice books rather than the subject of the nonsense poem that Alice reads in Through The Looking Glass.