kartik-v/yii2-widget-datepicker 小部件的问题

我无法让小部件在过滤器中工作。GridView 中的代码：

    [
        'label' => Yii::t('app', 'Дата'),
        'attribute' => 'document_date',
        'format' => 'raw',
        'filter' => DatePicker::widget([
            'attribute' => 'date_from',
            'attribute2' => 'date_to',
            'type' => DatePicker::TYPE_RANGE,
            'model' => $searchModel,
            'separator' => '-',
            'convertFormat' => true,
            'pluginOptions' => [
                'todayHighlight' => true,
                'weekStart'=>1, //неделя начинается с понедельника
                'autoclose' => true,
                'format' => 'dd.MM.yyyy'
            ],
            'readonly' => true
        ]),
        'value' =>  function($model){
            $time = strtotime($model->document_date);
            return Yii::t('app', 'от').' '.date('d.m.Y', $time).'<br><span class="text-muted">'.date('H:i:s', $time).'</span>';
            },
        'headerOptions' => ['class' => 'text-center','style'=>'width: 320px;'],
        'contentOptions' =>['class' => 'text-center'],
    ],

添加到模型中：

        public $date_from;
        public $date_to;

在搜索模型中：

    if ($this->document_date){
        $timestampFrom = strtotime($this->date_from);
        $timestampTo = strtotime($this->date_to);

        if ($timestampFrom && $timestampTo){
            $dateFrom = date("Y-m-d 00:00:00", $timestampFrom);
            $dateTo = date("Y-m-d 23:59:59", $timestampTo);
            $query
                ->andFilterWhere(['<=', 'orders.document_date', $dateTo])
                ->andFilterWhere(['>=', 'orders.document_date', $dateFrom])
            ;
        }
    }

将日期设置为小部件的任何部分时，它在 date_from 和 date_to 中都被替换。我究竟做错了什么？