Michael Heerdegen <michael_heerdegen@web.de> writes:

> [...] and `font-lock-set-defaults' finds that
>
>   (derived-mode-p font-lock-major-mode)
>
> fails so that it recomputes the `font-lock-keywords' from the
> defaults.  I guess we could prevent that happening?

This patch seems to fix the issue.  Good idea?