If the gconf var use_tabbar be changed, this method will be
        called and will show/hide the tabbar.

def tabbar_toggled(self, settings, key, user_data):
        """If the gconf var use_tabbar be changed, this method will be
        called and will show/hide the tabbar.
        """
        if settings.get_boolean(key):
            for n in self.guake.notebook_manager.iter_notebooks():
                n.set_property("show-tabs", True)
        else:
            for n in self.guake.notebook_manager.iter_notebooks():
                n.set_property("show-tabs", False)