title: Selectable <optgroup> in HTML <select> tag
body: <p>Is there any way to make the option group selectable?</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-html lang-html prettyprint-override"><code>&lt;select&gt;
    &lt;optgroup value="0" label="Parent Tag"&gt;
      &lt;option value="1"&gt;Child Tag&lt;/option&gt;
      &lt;option value="2"&gt;Child Tag&lt;/option&gt;
    &lt;/optgroup&gt;
  &lt;/select&gt;</code></pre>
  </div>
  </div>
  </p>