title: select2 does not render selected values
body: <p>I have a select2 element like this:</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>$(document).ready(function () {
      $('.select2').select2({
          multiple: true
      });
  });</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>.select2{
  width:100%
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://code.jquery.com/jquery-3.3.1.min.js"&gt;&lt;/script&gt;
  &lt;link href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/css/select2.min.css" rel="stylesheet" /&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.6-rc.0/js/select2.min.js"&gt;&lt;/script&gt;
  &lt;select name="test" class="select2" multiple='multiple'&gt;
      &lt;option value='A'&gt;A&lt;/option&gt;
      &lt;option value='B'&gt;B&lt;/option&gt;
      &lt;option value='C'&gt;C&lt;/option&gt;
      &lt;option value='D'&gt;D&lt;/option&gt;
  &lt;/select&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>For some reason, when I add value, it is not shown as selected, but upon posting data from form, I receive all values form this select. Example:</p>
  
  <p><a href="https://i.stack.imgur.com/2kcxv.png" rel="nofollow noreferrer">Options C and D are selected, in options dropdown they are highlighted as selected, but in "main" element, they are not.</a></p>
  
  <p>Once I save the form and page re-renders, select2 is now showing the selected values. <a href="https://i.stack.imgur.com/RXZkX.png" rel="nofollow noreferrer">See this picture.</a></p>
  
  <p>If I try to remove any value using the X, it will not get removed from "main" element, but it would be deselected from options and again, form will submit correct values.</p>
  
  <p>I tried to google but did not manage to find any help. The version of Select2 I am using is 4.0.5. Bootstrap v3 and jQuery 1.11.0 is also included in the page. I have tried changing order or including CSS and JS, but nothing seem to make any difference. Applying bootstrap theme for select2 did not help as well.</p>
  
  <p>Any idea what could be wrong?</p>