I am using gridView::FILTER_SELECT2 with multiple = TRUE and AllowClear = TRUE.
Problem 1: When I select single option it works fine but when I select another option it overwrites the first option and filter accordingly.
$gridColumns[] = [
            'attribute'=>'clubName',
            'headerOptions'=>[
                'style'=>'width: 15%'
            ],
            'filterType'=>GridView::FILTER_SELECT2,
            'filter'=>Clubs::getClubs(),
            'filterWidgetOptions'=>[
            'pluginOptions'=>['allowClear'=>true,
                'tags' => true,
                'tokenSeparators' => [',', ' '],
                'maximumInputLength' => 10
                ],
            'options'=>['id' => 'unique-select2-id'],
            ],
            'filterInputOptions'=>['placeholder'=>'Select Club'],
            'value' => function($model, $key, $index, $column){
                    return urldecode($model->header->club->name);
                },
        ];
<?= GridView::widget([
            'headerRowOptions'=>['class'=>'kartik-sheet-style'],
            'dataProvider' => $dataProvider,
            'filterModel' => $searchModel,
            'pjax' => true,
            'responsive' => true,
            'pjaxSettings' => [
                'options' => [
                    'enablePushState' => false,
                    'options' => ['id' => 'unique-pjax-id'] // UNIQUE PJAX CONTAINER ID
                ],
            ],
            'columns' => $gridColumns,
            'panel'=>[
                'type'=>GridView::TYPE_PRIMARY,
                'heading'=>$this->title,
            ],
            // set your toolbar
            'toolbar'=> [
                ['content'=>''
                ],
                '{export}','{toggleData}'
            ],
// set export properties
'export'=>[
            'fontAwesome'=>true
        ],
            'showPageSummary'=> true,
        ]); ?>
Problem2: When I try to remove selected option by clicking x , it doesn't clear the selection and throwing js error.
TypeError: args is undefined --- args.prevented = true;
				
                        
It looks like there is a related issue in yii2 tracker https://github.com/yiisoft/yii2/issues/4431