Your solution to moving "down" when one of the 4 big buttons is selected is a big hit :)
Big dropdown megamenu
They have made the following request: "And what would make it even better is if it returned to the top of the basic page once you closed that window."
I could add an "anchor" at the top of the page, if that would help in this solution. Or maybe it isn't needed.
What they are asking for is when someone clicks off of the megamenu, to close it, when it closes, the page returns to the very top, thus including the big slideshow at the top etc etc.