title: Flex item not expanding to 100% width until browser window is resized
body: <p>I have a Flexbox container in a React app with <code>flex-direction: row</code>. The container contains two tiles, both with <code>flex: 1</code>. Each occupies 50% of the width as shown below. This is expected.</p>
  
  <p><a href="https://i.stack.imgur.com/JxU8D.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JxU8D.png" alt="enter image description here"></a></p>
  
  <p>However, when the state of the component changes and only <code>Tile 1</code> is rendered, it still occupies only 50% of the width, not expanding to take up the full width. When I wiggle the browser window a bit, <code>Tile 1</code> expands to the full width. Note that the state of the component has not changed during the window resize, only that the tile now occupies the full width. I am thinking that I may have hit some React + Flexbox bug. Any ideas what this may be?</p>
  
  <p>Unfortunately I am not able to reproduce this issue with a minimal example. Here's the <a href="https://material-ui-playground.firebaseapp.com/tile-list" rel="nofollow noreferrer">live version</a> of the minimal example that works perfectly! The source code is <a href="https://github.com/nareshbhatia/material-ui-playground/blob/master/src/features/tile-list/tile-list.js" rel="nofollow noreferrer">here</a>.</p>
  
  <p>The rendered HTML and CSS are effectively as simple as the following:</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-css lang-css prettyprint-override"><code>body {
    font-family: Arial, Verdana, Helvetica, sans-serif;
  }
  
  .container {
    display: flex;
    flex-direction: row;
  }
  
  .content {
    flex: 1;
    min-width: 0;
    margin-right: 4px;
    padding: 4px;
    height: 60px;
    color: white;
    background-color: #2196f3;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="container"&gt;
    &lt;div class="content"&gt;
      Tile 1
    &lt;/div&gt;
    &lt;div class="content"&gt;
      Tile 2
    &lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>The real code is further wrapped using <a href="https://github.com/souporserious/react-measure" rel="nofollow noreferrer">react-measure</a> and <a href="https://github.com/oliviertassinari/react-swipeable-views" rel="nofollow noreferrer">react-swipeable-views</a>, but I don't think those are contributing to the issue.</p>