Subpixel Hinting in GTK-applications

Hello everybody. In my Gentoo system (I have also tried Gentoo 2012
livedvd) GTK-applications (for example: mousepad, gedit, leafpad,
Firefox, Chromium and all the websites opened in these two browsers)
do not use Subpixel Hinting. I have tried setting Subpixel Hinting
settings via KDE systemsettings, eselect fontconfig (enable
sub-pixel-rgb), .Xresources (Xft.rgba: rgb), xfce4-settings-manager
and mate settings manager. I have tried KDE, Xfce, Mate, pure Openbox.
Profiles: desktop or desktop/kde. If I change hinting style
(slight/medium/full) fonts in GTK-applications change, but it seems
like they ignore subpixel hinting settings. I have tried fonts:
Tahoma, Arial, Lucida Sans (for websites), DejaVuSans, LiberationSans
(for desktop applications). In KDE-applications everything is fine:
subpixel hinting is used, Konqueror displays fonts on websites
normally. Can you please help me? I am in desperation.