I have a sortable on which other sortable divs can be dropped. When this happends i want to show a messagebox. But my messagebox never shows. How can i display a messagebox when a div is placed down on my sortable div??

 

 $("#Category1").sortable({
  connectWith: ['#Category1', '#Category2', '.column'],
  revert: 'invalid',
  drop: function(event, ui) {
   alert ( 'this message never shows...' );
  }
 });