title: how to cancel drop event in jquery ui?
body: <p>Here is my <a href="http://jsfiddle.net/Sanju_Bollera/5vuzagkw/" rel="nofollow">JSFiddle</a> I want only one item to be dragged from each group(Fruits,Celebrity,Mobile Phones) to any one of the step. I tried by not allowing using return false, but return false doesn't seemed to work. Please help me not to drag and drop more than one element from each group to any of the rules.</p>
  
  <p>I can add atmost add only 3 items to any of the group.</p>
  
  <p>Here is my sample code which i wrote for not drop the element if the group is already present.</p>
  
  <pre><code>$("#Rule1List,#Rule2List,#Rule3List").on("drop",function  (element,ui) {
  
      $("#Rule1List&gt;li,#Rule2List&gt;li,#Rule3List&gt;li").each(function  (index) {
        if($(this).eq(index).hasClass($(ui.draggable).attr('class')))
        {
          console.log($(ui));
          return false;
        }
      });
  
    });
  </code></pre>