diff --git a/components/artboxtree/treegrid/TreeGridColumn.php b/components/artboxtree/treegrid/TreeGridColumn.php
index e1ee53a..52df812 100755
--- a/components/artboxtree/treegrid/TreeGridColumn.php
+++ b/components/artboxtree/treegrid/TreeGridColumn.php
@@ -19,9 +19,6 @@ use yii\helpers\Inflector;
  */
 class TreeGridColumn extends Object {
 
-    /**
-     * @var TreeGrid the grid view object that owns this column.
-     */
     public $grid;
 
     /**
diff --git a/components/artboxtree/treegrid/TreeGridWidget.php b/components/artboxtree/treegrid/TreeGridWidget.php
index 3d2b07d..0025158 100755
--- a/components/artboxtree/treegrid/TreeGridWidget.php
+++ b/components/artboxtree/treegrid/TreeGridWidget.php
@@ -4,6 +4,8 @@ namespace artweb\artbox\components\artboxtree\treegrid;
 
 use artweb\artbox\ecommerce\models\TaxOption;
 use Yii;
+use yii\base\InvalidConfigException;
+use yii\grid\DataColumn;
 use yii\helpers\Html;
 use yii\helpers\ArrayHelper;
 
@@ -41,14 +43,14 @@ class TreeGridWidget extends \artweb\artbox\components\artboxtree\ArtboxTreeWidg
     public $rowOptions = [];
 
     /**
-     * @var Closure an anonymous function that is called once BEFORE rendering each data model.
+     * @var \Closure an anonymous function that is called once BEFORE rendering each data model.
      * It should have the similar signature as [[rowOptions]]. The return result of the function
      * will be rendered directly.
      */
     public $beforeRow;
 
     /**
-     * @var Closure an anonymous function that is called once AFTER rendering each data model.
+     * @var \Closure an anonymous function that is called once AFTER rendering each data model.
      * It should have the similar signature as [[rowOptions]]. The return result of the function
      * will be rendered directly.
      */
@@ -196,7 +198,7 @@ class TreeGridWidget extends \artweb\artbox\components\artboxtree\ArtboxTreeWidg
             $cells[] = $column->renderDataCell($model, $key, $index, $i == 0, $this->levelSymbol);
             $i++;
         }
-        if ($this->rowOptions instanceof Closure) {
+        if ($this->rowOptions instanceof \Closure) {
             $options = call_user_func($this->rowOptions, $model, $key, $index, $this);
         } else {
             $options = $this->rowOptions;
--
libgit2 0.21.4