NVDA doesn't read first HTML child when focusing from parent on Firefox
<p>When using NVDA on Firefox it fails to read the first child when focusing from a container, but it is able to read the second child.</p>

<p>Generic Example: </p>

<pre><code>&lt;div class="container" tabindex="0"&gt;
  &lt;div class="child" aria-label="Child 1" tabindex="0"&gt;Child 1&lt;/div&gt;
  &lt;div class="child" aria-label="Child 2" tabindex="0"&gt;Child 2&lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>When <code>.container</code> is focused, and you hit tab to focus "Child 1", NVDA does not read "Child 1", but is silent. If you hit tab again NVDA reads "Child 2".</p>

<p>This reads correctly on Chrome with the ChromeVox addon.</p>

<p>Here is a codepen: <a href="http://codepen.io/anon/pen/WGyxom" rel="noreferrer">http://codepen.io/anon/pen/WGyxom</a></p>

<p>Is there some configuration that I'm missing to allow NVDA to read "Child 1" when focusing from <code>.container</code>?</p>