protected function compareActions(array $a, array $b)
    {
        $a = isset($a['priority']) ? $a['priority'] : 0;
        $b = isset($b['priority']) ? $b['priority'] : 0;
        $c = isset($action['isSubmittable']) && $action['isSubmittable'];

        return ($c || ($a === 0) || ($a >= $b));
    }