Ian Neal <iann_bugzilla@blueyonder.co.uk> has asked neil@parkwaycc.co.uk
<neil@httl.net> for superreview:
Bug 79603: Disable color controls when 'Use system color' is checked
https://bugzilla.mozilla.org/show_bug.cgi?id=79603

Attachment 313728: Onchange patch v1.1
https://bugzilla.mozilla.org/attachment.cgi?id=313728&action=edit

------- Additional Comments from Ian Neal <iann_bugzilla@blueyonder.co.uk>
Changes since v1.0a - addressed review comments:
* use onchange on preference.
* use preference value instead of checkbox setting.
* set disabled property on elements rather than attribute.