I have an 08 Sequoia and with the sunroof open there is a "flap", for lack of better description, on the front of the sunroof opening. This flap runs the width of the opening and moves up and down depending on speed. At low speed, it's up a little bit, but at higher speed it is retracted down. What is the function of this and why did they make it move up and down? Guess I'm wondering what the function of it is, seems like it's one more moving part to break, not that I've had any problems with it. Just curious more than anything.