Who's at fault with the key-map issues?

[Galen Boyer]

sqml-mode sets part of sgml-mode-map with
    (define-key map "\C-c\C-f" 'sgml-skip-tag-forward)

psgml-mode sets part of sgml-mode-map with
    (define-key sgml-mode-map "\C-c\C-f\C-e" 'sgml-fold-element)
    (define-key sgml-mode-map "\C-c\C-f\C-r" 'sgml-fold-region)
    (define-key sgml-mode-map "\C-c\C-f\C-s" 'sgml-fold-subelement)
    (define-key sgml-mode-map "\C-c\C-f\C-x" 'sgml-expand-element)


These clash when something like the following is in files that
get loaded.

(require 'sgml-mode)
(require 'psgml)

The error is:

   "Key sequence C-c C-f C-e uses invalid prefix characters"

brought about by C-c C-f being a keystroke in sqml-mode while
being defined as a prefix key in psgml-mode.

The actual sequence of loading for me is

(require 'xml-lite)
(require 'xae)

xml-lite requires sgml-mode, xaes require psgml.

So, it seems that the culprit is psgml since it didn't check with
sgml keymap before defining new keys, but I'm not sure...  

-- 
Galen Boyer