If the gconf var scroll_keystroke be changed, this method
        will be called and will set the scroll_on_keystroke in all
        terminals open.

def keystroke_toggled(self, settings, key, user_data):
        """If the gconf var scroll_keystroke be changed, this method
        will be called and will set the scroll_on_keystroke in all
        terminals open.
        """
        for i in self.guake.notebook_manager.iter_terminals():
            i.set_scroll_on_keystroke(settings.get_boolean(key))