When I command-z to undo some text editing, it works fine.
But when I command-shift-z (the standard for re-do) the text of the WHOLE post changes!!!
code in html view mode looks like
<p style="font-size: 29.25px; line-height: 42.75px;">These are the temporary portfolios of our Creative Talents.</p>
Also, the headers of the editor's left pannels (Posts, Media, Links, etc) grow up accordingly until the next refresh, when the page goes back to normal size, but not the damaged post.
Reducing the size of text on Firefox doesn't fix it.
Firefox 3.08, Intel Mac.