title: SortableJS - Disable sort on a specific element
body: <p>I'm having difficulty disabling sorting on a specific <code>li</code> in my <code>ul</code>.
  I'm using <a href="https://github.com/SortableJS/Sortable" rel="noreferrer">SortableJS</a>.</p>
  
  <pre><code>&lt;ul id="items"&gt;
      &lt;li class="static"&gt;
          &lt;div class="image"&gt;&lt;img src="image.jpg" /&gt;&lt;/div&gt;
          &lt;div class="text"&gt;Static&lt;/div&gt;
          &lt;div class="clearboth"&gt;&lt;/div&gt;
      &lt;/li&gt;
      &lt;li&gt;
          &lt;div class="image"&gt;&lt;img src="image.jpg" /&gt;&lt;/div&gt;
          &lt;div class="text"&gt;Dynamic&lt;/div&gt;
          &lt;div class="clearboth"&gt;&lt;/div&gt;
      &lt;/li&gt;
      &lt;li&gt;
          &lt;div class="image"&gt;&lt;img src="image.jpg" /&gt;&lt;/div&gt;
          &lt;div class="text"&gt;Dynamic&lt;/div&gt;
          &lt;div class="clearboth"&gt;&lt;/div&gt;
      &lt;/li&gt;
  &lt;/ul&gt;
  </code></pre>
  
  <p>One <code>li</code> with class <code>static</code> should NOT be sortable. The others should be sortable.</p>
  
  <pre><code>var el = document.getElementById('items');
  
  var sortable = new Sortable(el, {
      onUpdate: function (evt) {
          var itemEl = evt.item;
  
          // here happens some stuff
      },
      filter: '.js-remove',
      onFilter: function (evt) {
          // here happens some stuff
      }
  });
  </code></pre>
  
  <p>I <a href="https://stackoverflow.com/a/13885829/673991">know</a> you can do it in <a href="https://jqueryui.com/sortable/" rel="noreferrer">jQuery UI sortable</a> like this:</p>
  
  <pre><code>$( ".sortable" ).sortable({
      cancel: ".static"
  });
  </code></pre>
  
  <p>How can I do this in SortableJS?</p>