<ul class="contains-task-list">
<li class="task-list-item"><input type="checkbox" id="" disabled="" class="task-list-item-checkbox" checked=""> I have searched the <a href="https://github.com/callemall/material-ui/issues">issues</a> of this repository and believe that this is not a duplicate, although <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="263544855" data-permission-text="Title is private" data-url="https://github.com/mui/material-ui/issues/8580" data-hovercard-type="issue" data-hovercard-url="/mui/material-ui/issues/8580/hovercard" href="https://github.com/mui/material-ui/issues/8580">#8580</a> is certainly related and could be the same root cause.</li>
</ul>
<h2 dir="auto">Expected Behavior</h2>
<p dir="auto">Am able to use withTheme in my React 16 application</p>
<h2 dir="auto">Current Behavior</h2>
<p dir="auto">When using withTheme from material-ui@1.0.0-beta.16 with React 16, React gives the following warning, which is fatal to the execution of my app.</p>
<p dir="auto">Warning: Functions are not valid as a React child. This may happen if you return a Component instead of  from render. Or maybe you meant to call this function rather than return it.</p>
<h2 dir="auto">Steps to Reproduce</h2>
<p dir="auto">Here is an example of how I am using withTheme:</p>
<p dir="auto">const MyComponent = props =&gt; {<br>
// use props.theme.palette.text.primary<br>
};<br>
export default withTheme(MyComponent);</p>
<h2 dir="auto">Environment</h2>
<p dir="auto">Issue did not exist when using withTheme with React 15. Issue occurs post-upgrade of React.</p>
<table role="table">
<thead>
<tr>
<th>Tech</th>
<th>Version</th>
</tr>
</thead>
<tbody>
<tr>
<td>Material-UI</td>
<td>1.0.0-beta.16</td>
</tr>
<tr>
<td>React</td>
<td>react@16.0.0, react-dom@16.0.0</td>
</tr>
<tr>
<td>browser</td>
<td>Chrome  Version 61.0.3163.100</td>
</tr>
</tbody>
</table>
<p dir="auto">Adding an errorText dynamically makes all the following content jump unpleasantly.<br>
Perhaps the space for the error text could be reserved in advance, or it could animate the vertical motion instead?</p>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/113721/11031187/54dcdb68-86db-11e5-8284-6543c4bc2ff1.gif"><img src="https://cloud.githubusercontent.com/assets/113721/11031187/54dcdb68-86db-11e5-8284-6543c4bc2ff1.gif" alt="2" data-animated-image="" style="max-width: 100%;"></a></p>