title: material ui app bar not showing - reactjs
body: <p>Recently I updated my material ui to latest versions and updated my libraries in react js.</p>
  
  <p>Here's the Sample Code:</p>
  
  <pre><code>import React from 'react';
  import MuiThemeProvider from 'material-ui/styles/MuiThemeProvider';
  import AppBar from 'material-ui/AppBar';
  class HomePage extends React.Component {
      render() {
          return (
  
              &lt;div&gt;
                  &lt;div&gt;
  
                      &lt;MuiThemeProvider&gt;
                          &lt;div align="center"&gt;
  
                              &lt;AppBar
                                  title="Home Page"
                              /&gt;
                          &lt;/div&gt;
                      &lt;/MuiThemeProvider&gt;
                  &lt;/div &gt;
                  &lt;button id="login_button" type="button" class="btn btn-primary btn-block ml0 mr0 mt32"&gt;Login&lt;/button&gt;
  }
  </code></pre>
  
  <p>In here, the normal login button gets loaded. but the Appbar doesn't get load on top of it.
  It was working in old material ui library. but it fails in new one. I don't know what i am missing in it.  I checked <code>material-ui site</code> twice and more and updated all the libraries but unable to fix it. Help me with some solutions</p>