bug#2056: 23.0.60; Enabling flyspell degrades performance

[Marc Schwartz <marc_schwartz@me.com>]

Confirming that this behavior is still present using:

   GNU Emacs 23.0.93.1 (i386-apple-darwin9.6.2, NS apple- 
appkit-949.43) of 2009-05-11

I have the following in my .emacs:

   (load "/Users/marcschwartz/Downloads/Emacs/flyspell/flyspell")

   (autoload 'flyspell-mode "flyspell" "On-the-fly spelling checker." t)
   (add-hook 'tex-mode-hook 'flyspell-mode)
   (add-hook 'text-mode-hook 'flyspell-mode)

This is on a fully updated unibody MacBook Pro with OSX 10.5.6.

If I comment all of the above lines, the performance of emacs is fast  
when editing and scrolling through a large file. If I leave the lines  
as is, or comment the last three lines and manually enable flyspell  
mode after emacs has started up, all scrolling and general cursor  
motion slows down to a crawl.

I disabled the toolbar, as per comments in various posts, but that has  
no effect on emacs performance. This seems to be solely related to the  
use of flyspell mode.

I should also note that this same performance hit occurs with the  
Aquamacs devel branch built from their git repo, which is based upon  
emacs 23. The current release Aquamacs 1.7, which is based upon emacs  
22, does not exhibit this behavior.