<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/mui-org/material-ui/issues">issues</a> of this repository and believe that this is not a duplicate.</li>
</ul>
<h2 dir="auto">Expected Behavior</h2>

<p dir="auto">I just want to add the CircularProgress component to my app.</p>
<h2 dir="auto">Current Behavior</h2>

<p dir="auto">I have an error : "Element ref was specified as a string (wrapper) but no owner was set. You may have multiple copies of React loaded. (details: <a href="https://fb.me/react-refs-must-have-owner" rel="nofollow">https://fb.me/react-refs-must-have-owner</a>)."<br>
Replacing by another component like LinearProgress, is working fine.</p>
<h2 dir="auto">Steps to Reproduce (for bugs)</h2>

<p dir="auto">I have an another error trying to reproduce the bug<br>
<a href="https://codesandbox.io/s/pw5klx47v7" rel="nofollow">https://codesandbox.io/s/pw5klx47v7</a></p>
<h2 dir="auto">Context</h2>

<h2 dir="auto">Your Environment</h2>

<table role="table">
<thead>
<tr>
<th>Tech</th>
<th>Version</th>
</tr>
</thead>
<tbody>
<tr>
<td>Material-UI</td>
<td>0.20.0</td>
</tr>
<tr>
<td>React</td>
<td>16.0.0</td>
</tr>
<tr>
<td>browser</td>
<td>Chrome 63.0.3239.84</td>
</tr>
</tbody>
</table>
<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.</li>
</ul>
<h2 dir="auto">Expected Behavior</h2>

<p dir="auto">At mobile breakpoints, a <code class="notranslate">&lt;Snackbar /&gt;</code> positioned bottom-center should span the whole width of the window.</p>
<h2 dir="auto">Current Behavior</h2>

<p dir="auto">At mobile breakpoints, a <code class="notranslate">&lt;Snackbar /&gt;</code> positioned bottom-center takes up at maximum the center 50% of the window. If the message is shorter than ~50% of the window, the snackbar will be smaller.</p>
<h2 dir="auto">Steps to Reproduce (for bugs)</h2>

<p dir="auto">This bug is visible in the demo site under the "Positioned" section: <a href="https://material-ui-1dab0.firebaseapp.com/demos/snackbars/#positioned" rel="nofollow">https://material-ui-1dab0.firebaseapp.com/demos/snackbars/#positioned</a></p>
<ol dir="auto">
<li>Click "Bottom-Center".</li>
<li>Observe that the Snackbar is centered and not full width.</li>
<li>Click "Bottom-Left".</li>
<li>Observe that the Snackbar is full width.</li>
</ol>
<h2 dir="auto">Context</h2>
 
<p dir="auto">This bug is especially a problem when there are more than 8 or 9 words in the message, along with an action, and the snackbar looks oddly tall.</p>
<h2 dir="auto">Your Environment</h2>

<table role="table">
<thead>
<tr>
<th>Tech</th>
<th>Version</th>
</tr>
</thead>
<tbody>
<tr>
<td>Material-UI</td>
<td>v1.0.0-beta.15</td>
</tr>
<tr>
<td>React</td>
<td>v16.0.0</td>
</tr>
<tr>
<td>browser</td>
<td>Chrome</td>
</tr>
</tbody>
</table>