Hello, Alan.

> Could you be more specific, please - tell me which keywords weren't
> fontified, and exactly what you did for this to happen.

The screen shot was appended. (emacs -Q)

action.cc.png:
http://ftp.gnome.org/pub/GNOME/sources/gtkmm/3.0/gtkmm-3.0.1.tar.bz2
gtkmm-3.0.1/gtk/gtkmm/action.cc

The method name is not fontified.
But I execute M-oM-o in function, fontified correctly.

-- 
Kentaro Nakazawa