Comment 59 for bug 379761

Well, the truth as always lies somewhere between.

In fact font hinting may be set on per-application basis using Xft X resources. So any program you start up ends up with thsis Xft resources set up, no matter are the settings for font hinting set in .font.conf, in gconf or in .Xdefaults/.Xresources. The method of setting this up is up to implementator. KDE's way is to use .font.conf settings as the source for defaults. Gnome's way is to store this in gconf and commit them to X on the system startup/settings change program initialization/ This gets done by gnome-settings-daemon.

Firefox uses GTK+ as it's rendering backend on linux. But firefox by itself isn't a Gnome application - the only thing (well, almost) that is used from Gnome is widget engine and file chooser dialog. It is perfectly normal for firefox to be set up on a system without gnome-settings-daemon installed/running, and in such cases GTK+ appearence is contolled by .gtkrc files instead of gconfd/gnome-settings-daemon.

And here we come to a problem/bug described in this ticket: firefox-3.0 font hinting Xft X resources were controlled by gnome-settings-daemon, while firefox-3.5 don't. My proposal is that firefox-3.5 controls this settings by itself fetching defaults from .font.conf, and simply ignores gconf-settings-daemon's attemps to change them. It this proposal is right, then it shoud be fixed by upstream (mozilla.org), either by reverting firefox behaviour to the 3.0's state, or by adding special item to about:config which will allow to control whether shoud firefox read .fonts.conf and use it or not.