anchor.diff:  			, scroll: window
   			, tree: <%= tree %>
   			, onUpdate:function() {
  +			  reordering_button_enabled = false;
   				new Ajax.Updater('<%= list_id %>', '<%= update_url %>', 
   				{
   					asynchronous:true
   					, evalScripts:true
   					, parameters: Sortable.serialize('<%= list_id %>') + '&tree=<%= tree %>' + '&authenticity_token=' + encodeURIComponent($('reorder_authenticity_token').value)
  +					, onComplete: function(e) { reordering_button_enabled = true; }
   				});
   			}
   		});
  
positive.code: 	content_for :head do 
  %>
  <script type='text/javascript'>
  	FastInit.addOnLoad(function()
  	{
  		$('reorder_action').observe('click', enable_reordering);
  
negative.code: 		$('reorder_action').hide();
  		$('reorder_action_done').show();
  		
  		if (e) { e.stop(); }
  	}
  </script>
  <% end %>