His Girl Friday (1940)

Continuity mistake: While eating lunch with Walter, the front angle of Hildy shows her hands down. The rear angle shows her hand on her cheek.

Continuity mistake: When Hildy returns to the press room after taking Molly Malloy out, the wide shot shows her opening the door all the way. Then the close up shows her doing this again.

Continuity mistake: There is a scene when they are all in the press room when he's inside the desk. As Hildy goes to get water you can see she's wearing the black heels she's been wearing throughout the movie. In the next shot as she walks behind the table, if you look through the table legs you can see she's wearing a pair of flat white slippers/loafers.