Sticky subroutine headers

Not something I have seen in other editors, but would be very useful for me. It would be nice for subroutine/function/module/class declarations to act as a type of "sticky header" which would stay at the top of the screen until you have scrolled past the end of the structure. A good demonstration can be found on this page: http://www.noodlesoft.com/blog/2009/09/25/sticky-section-headers-in-nstableview/