You can find tthe instructions to enter the Red Pill Mode in http://hildon-app-mgr.garage.maemo.org/redpill.html
You can and should enter back to Blue Pill Mode after installing gtkextra.

GtkExtra does not replace anything. It is a complementary widget set for Gtk+. You can find more about it in http://gtkextra.sourceforge.net/.

Regards,

Julius
the developer of FuelPad