[Ur] urweb-mode speed issues

[Chris Casinghino]

The urweb emacs mode seems to be very slow on large files.  In
particular, scrolling down is very slow in basics.urs.  It starts off
at a reasonable speed, but as I scroll further down into the file I
have to wait longer and longer for each additional page - several
seconds for each page down by the time I hit line 400.  After the text
has been displayed into the buffer once, scrolling up and down is
quick (until I close emacs).

Is anyone else experiencing this?  Admittedly, my laptop is 3 years
old, but something must be wrong here.  I am running emacs 23 on
ubuntu 10.04.

--Chris