title: Overlay not working when I upgrade to jQuery 1.12.1
body: <p>Good day,</p>
  
  <p>I am upgrading my web application system jQuery to version 1.12.1. And found that the <code>overlay</code> is not working in new jQuery version.</p>
  
  <p>I am using ajax to pop out a dialog with overlay. Here is my ajax code:</p>
  
  <pre><code>$.ajax({
          async: false,
          url: locurl,
          data: dataPackage,
          success: function(result){
              createServiceModel();
              $("#viewService").dialog({
                  height: 645,
                  width: 720,
                  resizable: false,
                  modal: true,
                  autoOpen: true,
                  bgiframe: true,
                  overlay: {
                      opacity: 0.4, 
                      backgroundColor: "black"
                  }
              });
  
                  $("#serviceContent").append(result);
           },
           error: function (xhr, ajaxOptions, thrownError){
              if(xhr.status==403) alert("You are not allowed to proceed due to changes in your profile. Please re-log in again.");
              else alert("Connection Error. Please try again later. If error persisted, please contact System Administrator.");
          }
      });
  </code></pre>
  
  <p>This is working fine with my old jQuery.</p>
  
  <p>Here is the html code I copy from Chrome debug mode:</p>
  
  <pre><code>&lt;div class="ui-dialog-overlay" style="border-width: 0px; margin: 0px; padding: 0px; position: absolute; top: 0px; left: 0px; width: 1343px; height: 628px; opacity: 0.4; background-color: red; z-index: 1001;"&gt;&lt;/div&gt;
  
  &lt;div class="ui-dialog ui-draggable" tabindex="-1" 
      style="display:block;position:absolute;width:720px;height:645px;overflow:hidden;z-index:1002;outline:0px;top:5px;left:311.5px;;;"&gt;
      &lt;!-- other html code here --&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>I found that the <code>ui-dialog-overlay</code> is actually can find from <code>ui.dialog.js</code>.</p>
  
  <p>However, when I upgrade to jQuery UI 1.12.1, I found that <code>ui-dialog-overlay</code> no longer exists in the jquery-ui.js, but become <code>ui-dialog-overlays</code>.</p>
  
  <p>I downloaded the latest jQuery js files from <a href="http://jqueryui.com/download/" rel="nofollow noreferrer">http://jqueryui.com/download/</a></p>
  
  <p>Is it the <code>overlay</code> syntax changes in ajax code?
  I tried change the <code>overlay</code> by adding 's' on it to</p>
  
  <pre><code>overlays: {
              opacity: 0.4, 
              backgroundColor: "black"
          }
  </code></pre>
  
  <p>But still not working.</p>
  
  <p>Kindly advise.</p>