title: jQuery UI sortable and draggable prevent moving draggable item to sortable last child
body: <p>I am using the JQueryUI to implement drag and sort.</p>
  
  <p>The problem is how to make the sortable reject draggable item if the draggable item placed after the sortable last child?</p>
  
  <pre><code>&lt;ul id="draggable"&gt;
      &lt;li&gt;Drag Item 1&lt;/li&gt;
      &lt;li&gt;Drag Item 2&lt;/li&gt;
      &lt;li&gt;Drag Item 3&lt;/li&gt;
      &lt;li&gt;Drag item 4&lt;/li&gt;
  &lt;/ul&gt;
  
  &lt;ul id="sortable"&gt;
      &lt;li&gt;Item 1&lt;/li&gt;
      &lt;li&gt;Item 2&lt;/li&gt;
      &lt;li&gt;Item 3&lt;/li&gt; 
      &lt;li&gt;Last item&lt;/li&gt; //if I placed drag item after this, the sortable list reject the drag item
  &lt;/ul&gt;
  </code></pre>
  
  <ol>
  <li>I drag the Drag Item 2 to sortable</li>
  <li>If the the Drag Item 2 placed before the last child of sortable -> normal scenario happened</li>
  <li>If the the Drag Item 2 placed after the last child of sortable -> the sortable list reject the Drag Item 2</li>
  </ol>
  
  <p>Any Suggestion??
  Thx.</p>