This thread already explains what is needed more elegantly than I would. :-)
http://www.mail-archive.com/desktop-devel-list@gnome.org/msg17531.html

On Thu, 2009-10-22 at 14:48 -0400, Willie Walker wrote:
> Thanks Shaun!
> 
> > Epiphany and Evolution also both respond to F7 to enable
> > caret navigation.  (And, by the way, though Yelp stores
> > this in GConf, it also responds to F7.)  We're seeing
> > more and more applications use an HTML renderer for core
> > parts of their interfaces, such as Gwibber, and Empathy
> > with the Adium theme.
> > 
> > I also wonder if non-editable GtkTextView widgets should
> > be doing something here.
> 
> It's definitely something that is becoming more common, and I think you 
> either want it or not versus turning it on in one application and 
> disabling it in another.
> 
> > If we had a desktop-wide setting (possibly propagated by
> > an xsetting), then GTK+/Gecko/WebKit/etc could just pick
> > it up and do the right thing, without any extra work from
> > application developers.
> 
> The XSetting notion is interesting.  Which component would we file and 
> RFE for to get this?  gnome-settings-daemon?

Well, a few places.  We'd probably want to add something here:

http://www.freedesktop.org/wiki/Specifications/XSettingsRegistry

Then, I suppose there should be a GtkSettings property:

http://library.gnome.org/devel/gtk/stable/GtkSettings.html

And then, yes, gnome-settings-daemon would be responsible for
watching GConf (or whatever) and settings the XSetting.

--
Shaun