Flex auto margin not working in IE10/11
<p>I have a complex layout where I center various elements vertically and horizontally with flexbox.</p>

<p>The last element then has <code>margin-right:auto;</code> applied to push the elements left (and negate centering them).</p>

<p>This works correctly everywhere except on IE10/11 and has been driving me crazy.</p>

<p><strong>HTML/CSS sample:</strong></p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>#container {
  display: -ms-flexbox;
  display: -webkit-flex;
  display: flex;
  
  -ms-flex-flow: row wrap;
  -webkit-flex-flow: row wrap;
  flex-flow: row wrap;
  
  -ms-flex-pack: center;
  -webkit-justify-content: center;
  justify-content: center;
  
  -ms-flex-align: center;
  -webkit-align-items: center;
  align-items: center;
  
  -ms-flex-line-pack: center;
  -webkit-align-content: center;
  align-content: center;
}

#second-item {
  margin-right: auto;
}

/* just some colors - not important */
#container {
  height: 200px;
  width: 100%;
  background: red;
}
#container &gt; div {
  background: blue;
  padding: 10px;
  outline: 1px solid yellow;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id='container'&gt;
  &lt;div id='first-item'&gt;first item&lt;/div&gt;
  &lt;div id='second-item'&gt;second item&lt;/div&gt;
&lt;/div&gt;</code></pre>
</div>
</div>
</p>

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

<p>You'll see two items on the screen that should be left-aligned on the side of the red parent (i.e. they should both be centered, but the last item has <code>margin-right:auto;</code> applied and is filling the entire line, pushing the other item and itself on the side) - this is the correct behaviour. Except in IE10/11 where both items are incorrectly centered i.e. the second item's <code>margin-right:auto;</code> is ignored.</p>

<p>Any IE/flexbox experts out there that have encountered something like this before?</p>