title: Jquery Drag drop - One list with sortable and other list with draggable & droppable without sort
body: <p>I am trying to drag drop items between two lists, </p>
  
  <p>My requirements are,</p>
  
  <p><em>List A <strong>(with drag and drop to List B but not sortable)</strong>
  item 1
  item 2
  item 3</em></p>
  
  <p><em>List B <strong>(with sortable and drag/drop to List A)</strong>
  item 4
  item 5
  item 6</em></p>
  
  <p>i tried the <strong>.sortable()</strong>, but it makes the List A with sortable functionality,</p>
  
  <pre><code>&lt;ul id="sortable1" class="connectedSortable"&gt;
    &lt;li class="ui-state-default"&gt;Item 1&lt;/li&gt;
    &lt;li class="ui-state-default"&gt;Item 2&lt;/li&gt;
    &lt;li class="ui-state-default"&gt;Item 3&lt;/li&gt;
    &lt;li class="ui-state-default"&gt;Item 4&lt;/li&gt;
    &lt;li class="ui-state-default"&gt;Item 5&lt;/li&gt;
  &lt;/ul&gt;
  
  &lt;ul id="sortable2" class="connectedSortable"&gt;
    &lt;li class="ui-state-highlight"&gt;Item 1&lt;/li&gt;
    &lt;li class="ui-state-highlight"&gt;Item 2&lt;/li&gt;
    &lt;li class="ui-state-highlight"&gt;Item 3&lt;/li&gt;
    &lt;li class="ui-state-highlight"&gt;Item 4&lt;/li&gt;
    &lt;li class="ui-state-highlight"&gt;Item 5&lt;/li&gt;
  &lt;/ul&gt;
  
  $( function() {
      $( "#sortable1, #sortable2" ).sortable({
        connectWith: ".connectedSortable",
        beforeStop: function (event, ui) {
        console.log($(ui.helper).parent().attr('id'));
        console.log($(ui.placeholder).parent().attr('id'));
        if($(ui.helper).parent().attr('id') === 'sortable1' &amp;&amp; $(ui.placeholder).parent().attr('id') === 'sortable1')
        {
                  $(this).sortable('cancel');
            }
               },
      }).disableSelection();
    } );
  </code></pre>
  
  <p>I even tried to stop the sortable in beforeStop event, but shows me error</p>
  
  <p><strong>$(this).sortable('cancel');</strong></p>
  
  <p>Error:
  <strong>jquery-ui.js:16692 Uncaught TypeError: Cannot read property 'removeChild' of null</strong></p>
  
  <p>Please anyone help me out to resolve this case</p>