Harry Potter and the Order of the Phoenix (2007)

Continuity mistake: There are two scenes during which Harry is shown having visions of the Dept of Mysteries while he is asleep. The first scene occurs after Harry's confrontation with Seamus in the Gryffindor common room. There are shots of Harry lying in bed wearing a short sleeve, crew neck tee shirt, but when he is startled awake by the vision of Voldemort, he sits up wearing a buttoned henley tee. The next day is the first day of Defence Against the Dark Arts class with Umbridge. That last shot of Harry in the henley tee shirt was cut from a later scene. Later in the film, when Harry has the vision of Arthur Weasley's attack, he is wearing the henley tee shirt. (00:34:00 - 01:09:35)

Super Grover ★

Dolores Umbridge: What? Do something! Tell them I mean no harm!
Harry Potter: I'm sorry Professor. I must not tell lies.

Trivia: The director and other persons of importance had cut Kreacher out of the film. JKR told them that she couldn't tell them what to do, but the final film wouldn't make sense if they didn't introduce Kreacher in this one. Five minutes later, Kreacher was back in.

Question: When Umbridge has Harry, his friends and the Slytherin students in her office, she asks Harry if he was going to warn Dumbledore. When he says he wasn't, she responds by slapping him in the face. In the background, Draco has a look of shock on his face. Considering the fact that he hates Harry, why would he react this way?