<h3 dir="auto">Problem description</h3>
<p dir="auto">I'm getting the followinig warning when I use the closeIcon property on a CardTitle:</p>
<blockquote>
<p dir="auto">Warning: Unknown prop <code class="notranslate">closeIcon</code> on </p><div dir="auto"> tag. Remove this prop from the element. For details, see <a href="https://fb.me/react-unknown-prop" rel="nofollow">https://fb.me/react-unknown-prop</a><p dir="auto"></p>
</div></blockquote>
<p dir="auto">However, the element is working just fine, the icon is being displayed and everything works fine.</p>
<h3 dir="auto">Link to minimal working code that reproduces the issue</h3>
<p dir="auto">Hope this link is correct:</p>
<p dir="auto"><a href="https://www.webpackbin.com/bins/-KjUqpCIvL3w31h-YqlI" rel="nofollow">https://www.webpackbin.com/bins/-KjUqpCIvL3w31h-YqlI</a></p>
<p dir="auto">Here is the code in any case. Just open the browsers console.</p>
<div class="highlight highlight-source-js notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="import React from 'react';
import { AppBar } from 'material-ui';
import FlatButton from &quot;material-ui/FlatButton&quot;;
import SvgIconAddShoppingCart from &quot;material-ui/svg-icons/action/add-shopping-cart&quot;;
import Add from &quot;material-ui/svg-icons/content/add&quot;;
import {Card, CardActions, CardHeader, CardMedia, CardTitle, CardText} from 'material-ui/Card';



const HelloWorld = () =&gt; (
  
   &lt;Card expandable&gt;
    &lt;CardTitle title=&quot;Users&quot; closeIcon={&lt;Add/&gt;} actAsExpander showExpandableButton /&gt;
    &lt;CardText expandable&gt;
      &lt;FlatButton label=&quot;add&quot; icon={&lt;SvgIconAddShoppingCart /&gt;} /&gt;
    &lt;/CardText&gt;
    &lt;/Card&gt;

);

export default HelloWorld;"><pre class="notranslate"><span class="pl-k">import</span> <span class="pl-v">React</span> <span class="pl-k">from</span> <span class="pl-s">'react'</span><span class="pl-kos">;</span>
<span class="pl-k">import</span> <span class="pl-kos">{</span> <span class="pl-v">AppBar</span> <span class="pl-kos">}</span> <span class="pl-k">from</span> <span class="pl-s">'material-ui'</span><span class="pl-kos">;</span>
<span class="pl-k">import</span> <span class="pl-v">FlatButton</span> <span class="pl-k">from</span> <span class="pl-s">"material-ui/FlatButton"</span><span class="pl-kos">;</span>
<span class="pl-k">import</span> <span class="pl-v">SvgIconAddShoppingCart</span> <span class="pl-k">from</span> <span class="pl-s">"material-ui/svg-icons/action/add-shopping-cart"</span><span class="pl-kos">;</span>
<span class="pl-k">import</span> <span class="pl-v">Add</span> <span class="pl-k">from</span> <span class="pl-s">"material-ui/svg-icons/content/add"</span><span class="pl-kos">;</span>
<span class="pl-k">import</span> <span class="pl-kos">{</span><span class="pl-v">Card</span><span class="pl-kos">,</span> <span class="pl-v">CardActions</span><span class="pl-kos">,</span> <span class="pl-v">CardHeader</span><span class="pl-kos">,</span> <span class="pl-v">CardMedia</span><span class="pl-kos">,</span> <span class="pl-v">CardTitle</span><span class="pl-kos">,</span> <span class="pl-v">CardText</span><span class="pl-kos">}</span> <span class="pl-k">from</span> <span class="pl-s">'material-ui/Card'</span><span class="pl-kos">;</span>



<span class="pl-k">const</span> <span class="pl-v">HelloWorld</span> <span class="pl-c1">=</span> <span class="pl-kos">(</span><span class="pl-kos">)</span> <span class="pl-c1">=&gt;</span> <span class="pl-kos">(</span>
  
   <span class="pl-c1">&lt;</span><span class="pl-ent">Card</span> <span class="pl-c1">expandable</span><span class="pl-c1">&gt;</span>
    <span class="pl-c1">&lt;</span><span class="pl-ent">CardTitle</span> <span class="pl-c1">title</span><span class="pl-c1">=</span><span class="pl-s">"Users"</span> <span class="pl-c1">closeIcon</span><span class="pl-c1">=</span><span class="pl-kos">{</span><span class="pl-c1">&lt;</span><span class="pl-ent">Add</span><span class="pl-c1">/</span><span class="pl-c1">&gt;</span><span class="pl-kos">}</span> <span class="pl-c1">actAsExpander</span> <span class="pl-c1">showExpandableButton</span> <span class="pl-c1">/</span><span class="pl-c1">&gt;</span>
    <span class="pl-c1">&lt;</span><span class="pl-ent">CardText</span> <span class="pl-c1">expandable</span><span class="pl-c1">&gt;</span>
      <span class="pl-c1">&lt;</span><span class="pl-ent">FlatButton</span> <span class="pl-c1">label</span><span class="pl-c1">=</span><span class="pl-s">"add"</span> <span class="pl-c1">icon</span><span class="pl-c1">=</span><span class="pl-kos">{</span><span class="pl-c1">&lt;</span><span class="pl-ent">SvgIconAddShoppingCart</span> <span class="pl-c1">/</span><span class="pl-c1">&gt;</span><span class="pl-kos">}</span> <span class="pl-c1">/</span><span class="pl-c1">&gt;</span>
    <span class="pl-c1">&lt;</span><span class="pl-c1">/</span><span class="pl-ent">CardText</span><span class="pl-c1">&gt;</span>
    <span class="pl-c1">&lt;</span><span class="pl-c1">/</span><span class="pl-ent">Card</span><span class="pl-c1">&gt;</span>

<span class="pl-kos">)</span><span class="pl-kos">;</span>

<span class="pl-k">export</span> <span class="pl-k">default</span> <span class="pl-v">HelloWorld</span><span class="pl-kos">;</span></pre></div>
<h3 dir="auto">Versions</h3>
<ul dir="auto">
<li>Material-UI: 0.18</li>
<li>React: 15</li>
<li>Browser: Chrome</li>
</ul>
<h3 dir="auto">Description</h3>
<h3 dir="auto">Images &amp; references</h3>
<p dir="auto"><a target="_blank" rel="noopener noreferrer nofollow" href="https://cloud.githubusercontent.com/assets/2270425/25776319/8d140244-32bb-11e7-9955-f18ac6773ec1.png"><img src="https://cloud.githubusercontent.com/assets/2270425/25776319/8d140244-32bb-11e7-9955-f18ac6773ec1.png" alt="image" style="max-width: 100%;"></a></p>
<h3 dir="auto">Problem description</h3>
<p dir="auto">When using the <code class="notranslate">closeIcon</code> prop on CardTitle, the selected icon is displayed but a warning that the prop is passed to a <code class="notranslate">div</code> is displayed in the console.</p>
<h3 dir="auto">Link to minimal working code that reproduces the issue</h3>
<p dir="auto"><a href="https://www.webpackbin.com/bins/-Kjal6iMWuKp0Lg-1DB9" rel="nofollow">https://www.webpackbin.com/bins/-Kjal6iMWuKp0Lg-1DB9</a></p>
<h3 dir="auto">Versions</h3>
<ul dir="auto">
<li>Material-UI: 0.17.1</li>
<li>React: 15.4.2</li>
<li>Browser: Chrome</li>
</ul>