title: jQuery UI draggable locking divs
body: <p>I wrote some kind of that: <a href="http://jsfiddle.net/py3DE/203/" rel="nofollow noreferrer">http://jsfiddle.net/py3DE/203/</a> but when element is dragged into proper container, we can override it by dragging other div into its area. Could you tel me how i can block dragged elements, and if someone will try to override any element, div returns back into area with undragged divs?</p>
  
  <pre><code>if (!ui.draggable.closest('.empty').length) item = item.draggable()'
  </code></pre>