title: Allow drag and drop of an element containing an iframe
body: <p>I'm trying to have a very basic drag and drop. It's working fine by just setting <code>draggable = "true"</code>, but doesn't seem to work when the draggable element contains an iframe.</p>
  
  <p>I have searched everywhere and met many complex problems with iframes, but none being about my specific problem.</p>
  
  <p>As you can see, only the area that is not covered by the iframe is draggable, while I would want to drag the whole container. </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>div {
      width: 300px;
      height: 100px;
      background: #A1DB6A;
  }
  iframe {
      border: 0;
      height: 80px;
      width: 100%;
      background: #ddd;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div draggable="true"&gt;
      &lt;iframe src=""&gt;&lt;/iframe&gt;
  &lt;/div&gt;
  &lt;br/&gt;
  &lt;span&gt;Only the green handle is draggable, but I want the whole container to be.&lt;/span&gt;</code></pre>
  </div>
  </div>
  </p>