public function form($instance)
    {
        $default = array(
                'title' => '',
                'instance' => null,
        );
        $instance = wp_parse_args((array) $instance, $default);
        $title_id = $this->get_field_id('title');
        $title_name = $this->get_field_name('title');
        echo '<p>
				<label for="'.$title_id.'">'.__('Title').
            ': <input type="text" class="widefat" id="'.$title_id.'" name="'.$title_name.'" value="'.esc_attr($instance ['title']).'" />
			</label></p>';

        $instance_id = $this->get_field_id('instance');
        $instance_name = $this->get_field_name('instance');

        $moufManager = MoufManager::getMoufManager();
        $instances = $moufManager->findInstances('Mouf\\Html\\HtmlElement\\HtmlElementInterface');
        sort($instances);

        echo '<p>
				<label for="'.$instance_id.'">'.__('Instance').':
				<select class="widefat" id="'.$instance_id.'" name="'.$instance_name.'" >
					';
        foreach ($instances as $name) {
            if ($moufManager->isInstanceAnonymous($name)) {
                continue;
            }
            ?>
			<option value="<?php echo esc_attr($name);
            ?>" <?php if ($name == $instance ['instance']) {
    echo "selected='selected'";
}
            ?>><?php echo esc_html($name);
            ?></option>
			<?php

        }
        echo '
				</select>
			</label></p>';
    }