title: jQuery UI sortable scroll helper element offset Firefox issue
body: <p>I have a problem with a jQuery UI 1.7.2 sortable list in Firefox 3.6, IE7-8 work fine. When I'm scrolled down a bit, the helper element seems to have an offset of the same height that I'm
  scrolled down from the mouse pointer which makes it impossible to see which item you originally started dragging.
  How do I fix this or work around the issue? If there is no fix what is a really good alternative drag-able plugin?</p>
  
  <p>Here are my initialization parameters for the sortable.</p>
  
  <pre><code>$("#sortable").sortable( {placeholder: 'ui-state-highlight'  } );
  $("#sortable").disableSelection();
  </code></pre>