quick ‘n dirty fix till extension is wmpl compatible
/wp-content/plugins/woocommerce-multiple-free-gift/lib/WFG_Frontend.class.php:189
// 15072016 q23 enhance for english product
//check if gift item is valid
self::__get_actual_settings();
if( !WFG_Product_Helper::crosscheck_gift_items( $_POST['wfg_free_items'], $this->_wfg_products ) && $_POST['wfg_free_items'][0] !== [ID OF PRODUCT] ) {
return;
}
/wp-content/plugins/woocommerce-multiple-free-gift/lib/WFG_Frontend.class.php:280
// 15072016 q23 enhance for english product
if( ! $this->_wfg_criteria || ! WFG_Product_Helper::crosscheck_gift_items( $cart_items, $this->_wfg_products ) && $cart_items !== [ID OF PRODUCT]) {
//remove gift products
if( $this->__remove_gift_products() ) {
$this->__set_notice_text();
}
}