[OS X Emacs] window-height trouble

[Chris Beard]

Hello,
I'm trying to use chop.el, a binary search for emacs
[http://fresh.homeunix.net/%7Eluke/misc/emacs/chop.el], that uses the
function "window-height" (basically can jump half the window height,
then jump half of that up or down, etc, until you're where you want to
be).

In Aquamacs it acts screwy, and it looks like window-height doesn't
work in it. I'm not too experienced at elisp, but I evaluated
(window-height), and the integer 36 came up in *Messages* buffer. The
line numbering shows the buffer where I evaluated it is 48 lines long
(though the scratch buffer numbering appears to actually be 36 lines
long).

Do Emacs 23 or Aquamacs have a different function that returns the
height of the window that I should be using instead? Or does Aquamacs
just have a difficult way of determining the height with the function?

Thanks
Chris