title: jQuery UI Autocomplete - _renderItem not firing on first paste
body: <p>I'm trying to get a custom rendered autocomplete label to populate when an input is pasted in. Here is a fiddle:</p>
  
  <p><a href="https://jsfiddle.net/sq5xyLas/" rel="nofollow noreferrer">https://jsfiddle.net/sq5xyLas/</a></p>
  
  <p>To test, copy <code>jQuery</code> to clipboard, and then paste it in the input textbox. Nothing happens. Remove that entry and paste it again, and the search fires. Why does the <code>.autocomplete("instance")._renderItem</code> not fire on the first paste? </p>
  
  <pre><code>var projects = [{
    value: "jquery",
    label: "jQuery",
    desc: "the write less, do more, JavaScript library",
    icon: "jquery_32x32.png"
  }, {
    value: "jquery-ui",
    label: "jQuery UI",
    desc: "the official user interface library for jQuery",
    icon: "jqueryui_32x32.png"
  }, {
    value: "sizzlejs",
    label: "Sizzle JS",
    desc: "a pure-JavaScript CSS selector engine",
    icon: "sizzlejs_32x32.png"
  }];
  
  $(input).autocomplete({
    delay: 200,
    minLength: 3,
    source: projects,
  }).autocomplete("instance")._renderItem = function(ul, resultItem) {
    console.log("A paste event has happened")
    return $("&lt;li&gt;")
      .append("&lt;div class='autocomplete-item'&gt;&lt;div class='autocomplete-img-container'&gt;&lt;/div&gt;&lt;div&gt; " + resultItem.label + "&lt;/div&gt;&lt;/div&gt;")
        .appendTo(ul);
    };
  }
  &lt;/script&gt;
  &lt;textarea id="textarea" class="small-input" placeholder="Add a item"  onkeyup="showResult(this)"&gt;&lt;/textarea&gt;
  </code></pre>
  
  <p><strong>Update</strong></p>
  
  <p>Updated source to</p>
  
  <pre><code>     source: function(request, response) {    
          //Do some AJAX
      }
  </code></pre>
  
  <p>however the <code>_renderItem</code> was still not firing.</p>
  
  <p>Adding:</p>
  
  <pre><code>  if(dynamicSource){
          response( dynamicSource);
      } 
      else{
          response({});
      }
  </code></pre>
  
  <p>Solved it.</p>