having seen the movie 10 times on a digital screen. I can assure you, mace windu is working with darth sidious. 1. he has a different lightsaber 2. he looks nervous most of the time.like he is hiding something from yoda. watch closely. 3. when obi wan reports in and talks about sifo dyas. windu begins to get nervous again. he immediately takes control and says "no". then yoda looks at him suspiciously. he is covering for someone. 4. he keeps reminding everyone that anakin is the one that will bring balance to the force. he worked with sidious in episode 1 to find the chosen one. he is helping sidious. 5. he sent anakin to protect padme. knowing it would be suicide. look at obi wan's face when mace windu gives the order. mace is trying to seperate the two. so they can fail 6.in episode 1. he makes choices to danger the lives of the jedi. 7. he is the one who erased the archives. only a jedi could do that. 8. he is spying on yoda. notice how he is always around him. watching him. cautiously. 9. he sacrificed all the jedi in the arena. taking them all there. knowing they would all die. knowing they didint have a chance. this is the proof.