Could this be just one of those situations, shall we say "plot hole" When Hitchcock was faced with a question he couldn't answer, he is known to say "Its only a movie".
It's a shame Hitchcock didn't direct GF2. Then we'd know who opened the drapes - Hitchcock!
If they hadn't cut all of Manolo's scenes from the Trilogy, we'd have the answers to many of these questions.
"Generosity. That was my first mistake." "Experience must be our only guide; reason may mislead us." "Instagram is Twitter for people who can't read."
