echo $form->field($model, 'subject')->widget(\softcommerce\chosen\ChosenSelect::className(),[
                    'items' => [
                        'first' => 'First',
                        'second' => 'Second'
                    ],
                ]); 

   echo \softcommerce\chosen\ChosenSelect::widget([
        'name'  => 'select',
        'items' => BooleanEnum::listData(),
        'options' => [
            'width' => '95%'
        ]
    ]);