Button.php
public function run()
    {
        $this->registerPlugin('button');
        $this->label = $this->getLabel();
        if ($this->enableIcon) {
            $this->label .= Icon::widget(['label' => $this->icon,'options' => $this->iconOptions]);
        }
        return Html::tag($this->tagName, $this->label, $this->options);
    }
public function run()
    {
        $this->registerPlugin('button');
        $this->label = $this->getLabel();
        if ($this->enableIcon) {
            $this->label .= Icon::widget(['label' => $this->icon,'options' => $this->iconOptions]);
        }
        return Html::tag($this->tagName, $this->label, $this->options);
    }
Renders the widget.