title: Prevent drop of list item in JqueryUI sortable
body: <p>I have two lists  <code>#sortable1</code> and <code>#sortable 2</code> which are connected sortables, as shown in this <a href="http://jqueryui.com/demos/sortable/#connect-lists" rel="noreferrer">example</a>.</p>
  
  <p>You can drag and drop list items from <code>sortable1</code> to <code>sortable 2</code>. However, if an item in <strong>sortable 1</strong> contains the class "number", I want to <strong>prevent</strong> the drop on <strong>Sortable2</strong> and thus make the dragged item drop back into <strong>sortable 1</strong>. </p>
  
  <p>I have used the following on sortable2:</p>
  
  <pre><code>receive: function (event, ui) {
              if ($(ui.item).hasClass("number")) {
                  $(ui.item).remove();
              }
  </code></pre>
  
  <p>but it deletes the list item from both tables altogether. Any help will be appreciated.</p>