Kartik Depdrop widget problem

I am using the Kartik Depdrop widget.

Everything is working fine except in the situation where I have not selected a value on creation of new record, on update the dependent field should show “Please select” whereas it is showing the first value in the drop-down and it is getting saved on update, whereas I want the value of ‘please select’ i.e. null even on update to be saved depending on the situation.

Example- I select a room-category - dependant value is packages, which can be null as well. So I didn’t select any value in the dependent field packages. But when I come to update the form the first value in the drop-down is showing by default, whereas I want the please select as the default. How can correct this?

My code in _form.php is like this:

$form->field($model, 'package')->widget(DepDrop::classname(), [                            

                'data'=>ArrayHelper::map(\app\models\Package::find()->all(), 'id', 'package_name' ),




               'url'=>  \yii\helpers\Url::to(['patient-detail/subcat']),               



Note:If I am selecting a value in the dependant dropdown on creation, then the value on update is showing correctly.

Hello any solution on this?