       event.preventDefault()
       return
 
-    event.originalEvent.dataTransfer.setData 'atom-event', true
+    event.originalEvent.dataTransfer.setData 'atom-event', 'true'
 
     el = $(event.target).closest('.sortable')
     el.addClass 'is-dragging'



  onDrop: (event) =>
    unless event.originalEvent.dataTransfer.getData('atom-event') == true
      event.preventDefault()
      event.stopPropagation()
      return

    @find(".is-dragging").removeClass 'is-dragging'

  onDragOver: (event) =>
    unless event.originalEvent.dataTransfer.getData('atom-event') is 'true'
      event.preventDefault()
      event.stopPropagation()
      return
