public function Field($properties = array())
    {
        $editables = $this->editableItems();
        $customcartdata = array(
            'Items' => $editables,
        );
        // NOTE: this was originally incorrect - passing just $editables and $customcartdata
        // which broke modules like Display_Logic.
        $this->extend('onBeforeRender', $this, $editables, $customcartdata);

        return SSViewer::execute_template(
            $this->template,
            $this->cart->customise($customcartdata),
            array('Editable' => true)
        );
    }