src/collections/Message.php
public function initOptions()
    {
        Ui::addCssClasses($this->options, ['ui', 'message']);
        if (!empty($this->header) && isset($this->header['options'])) {
            Ui::addCssClass($this->header['options'], 'header');
        }
        if (isset($this->icon)) {
            Ui::addCssClass($this->options, 'icon');
        }
    }
public function initOptions()
    {
        Ui::addCssClasses($this->options, ['ui', 'message']);
        if (!empty($this->header) && isset($this->header['options'])) {
            Ui::addCssClass($this->header['options'], 'header');
        }
        if (isset($this->icon)) {
            Ui::addCssClass($this->options, 'icon');
        }
    }
Initializes the widget options