protected function renderCloseButton()
    {
        if ($this->closeButton !== null) {
            $tag   = ArrayHelper::removeValue($this->closeButton, 'tag', 'a');
            $label = ArrayHelper::removeValue($this->closeButton, 'label', '&times;');
            if ($tag === 'button' && !isset($this->closeButton['type'])) {
                $this->closeButton['type'] = 'button';
            }
            Html::addCssClass($this->closeButton, Enum::DIALOG_CLOSE);
            return \CHtml::tag($tag, $this->closeButton, $label);
        } else {
            return null;
        }
    }