Jquery sortable + clone

Jquery sortable + clone

Hi All,

There are two ul list (list A & list B). I would like to develop and drag function so that users can drag the items in list A to list B and vice versa. However, after the items is dragged, it will be disappear in the original list. How can I keep the original item in the original list?

Below are my codes
<ul id="sortable4" class="connected sortable list1">
   <li>Item 1
   <li>Item 2
   <li>Item 3
   <li>Item 4
   <li>Item 5
   <li>Item 6
</ul>
<ul id="sortable5" class="connected sortable list2">
   <li class="highlight">Item 1
   <li class="highlight">Item 2
  <li class="highlight">Item 3
  <li class="highlight">Item 4
  <li class="highlight">Item 5
   <li class="highlight">Item 6
</ul>

<script>
$('.sortable').sortable({
   connectWith: '.sortable'
});
</script>