Hi Glenn,

Sorry, I was being sloppy.

I tried to minimise the problem and enabling flyspell in the XML file
seems to be the culprit. So:

emacs -Q
M-x file-find "...xml file I gave you..."
M-x flyspell-mode
... go to final comment line...
M-; (i.e. M-x uncomment-region)


I did a (profiler-start) with (setq debug-on-quit t) and got this:

- flyspell-post-command-hook                                     1994  81%
 - byte-code                                                     1994  81%
  - flyspell-word                                                1992  81%
   - sgml-mode-flyspell-verify                                   1989  81%
    - sgml-lexical-context                                       1985  81%
     - sgml-parse-tag-backward                                   1985  81%
      - byte-code                                                1985  81%
       - forward-sexp                                            1985  81%
        - nxml-forward-balanced-item                             1985  81%
         - nxml-forward-single-balanced-item                     1985  81%
          - funcall                                              1985  81%
           + #<compiled 0xf573b1>                                1949  80%