[OS X Emacs] seeing artifacts from certain characters

[Jonathan Swartz]

I am seeing artifacts from certain characters (e.g. "@") when I  
navigate through a buffer, or when Emacs moves the contents of my  
buffer.

For example, here's a buffer after loading:

     http://i28.tinypic.com/2079w7c.jpg

and here's what happens if I hit "ctrl-k" six times:

     http://i30.tinypic.com/2cdg6x0.jpg

The effects are more pronounced with white-on-black, which is my usual  
setup:

     http://i31.tinypic.com/30avqtj.jpg

Hitting control-L or running (redraw-frame (selected-frame)) makes the  
artifacts disappear.

This is OS X 10.5.7, Emacs 22.3.1 (downloaded from http://porkrind.org/emacs/Emacs-22.3-i386-10.5.7.dmg) 
, with no .emacs or other customizations. I've seen the same behavior  
with the latest CVS snapshot, and with the Carbon emacs package from http://homepage.mac.com/zenitani/emacs-e.htmlD 
. I've also seen similar behavior in Aquamacs, although I couldn't get  
this particular example to work because the default font is different  
and I can't figure out how to change it to match.

Has anyone else seen this? I've been living with it for a long time,  
but it is slowly driving me crazy.

Thanks!
Jon