public function actionUpdate()
    {
        $activeTheme = ThemeManager::getActiveTheme();
        $model = new DynamicModel(['activeIndex' => $activeTheme === false ? false : key($activeTheme)]);
        $model->addRule('activeIndex', 'safe');

        if ($model->load(Yii::$app->request->post())) {
            
            ///radioList:options:unselect: string, the value that should be submitted when none of the radio buttons is selected. You may set this option to be null to prevent default value submission. If this option is not set, an empty string will be submitted.
            ///@see http://docs.huihoo.com/yii/2.0/yii-helpers-basehtml.html#activeRadioList()-detail
            ThemeManager::setActiveTheme($model->activeIndex === '' ? false : $model->activeIndex);

            Yii::$app->session->setFlash('success', Module::t('message', 'Update succeed.'));
            return $this->refresh();
        }

        ///[v0.2.3 (ADD# radioList itme option)]
        return $this->render('update', ['model' => $model, 'themes' => ThemeManager::getThemes()]);
    }