title: Select2 kartik number value change to index value
body: <p>I have data like this: <br/>
  <a href="https://i.stack.imgur.com/yp2aH.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/yp2aH.jpg" alt="enter image description here"></a></p>
  
  <p>I use these data to fill the select2 kartik combobox, this is my yii2 code,</p>
  
  <pre><code>echo \kartik\widgets\Select2::widget([
                                  'attribute' =&gt; 'pembuatSoal_id',
                                  'model' =&gt; $model,
                                  'data' =&gt; array_merge(["" =&gt; ""], \yii\helpers\ArrayHelper::map(\app\models\ViewUsernameGuru::find()-&gt;all(), "uname", "nama")),
                                  'options' =&gt; ['placeholder' =&gt; 'Pilih Guru...', 'id' =&gt; 'guru-id', 'class' =&gt; "form-control"],
                                  'pluginOptions' =&gt; [
                                      'allowClear' =&gt; true,
                                      'theme' =&gt; \kartik\widgets\Select2::THEME_BOOTSTRAP
                                  ],
                              ]);
  </code></pre>
  
  <p><strong>uname</strong> field as the value of the select2 and nama as the display value. but the result is like this:<br/>
  <a href="https://i.stack.imgur.com/eLytB.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/eLytB.jpg" alt="enter image description here"></a></p>
  
  <p>But when The value of uname field is number, select2 automaticly change with the array index of select2 items.</p>
  
  <p>Hope some body give me the solve.</p>
  
  <p>Thanks.</p>