title: mCustomScrollbar don't update after add new element
body: <p>This full my code at <a href="https://jsfiddle.net/hoanghoang3009/cbvmxrpk/" rel="nofollow noreferrer">jsfiddle</a>. After I add new list element by jquery, I use update to scrollbar update new list but new list overflow out tag ul store it.</p>
  
  <p>This code to create list element dynamic (line 46-50 in jsfiddle):</p>
  
  <pre><code>    var d = new Date();
      var currentYear = d.getFullYear();
          for (var i=1990; i&lt;=currentYear; i++) {
          $("#expandYear ul").append("&lt;li&gt;&lt;a href=\"#\"&gt;"+ i +"&lt;/a&gt;&lt;/li&gt;&lt;li role=\"separator\" class=\"divider\"&gt;&lt;/li&gt;");
      }
  </code></pre>
  
  <p>This code to update mcustom scrollbar (line 52-61 in jsfiddle):</p>
  
  <pre><code>   $("#expandYear ul").mCustomScrollbar({ 
        advanced:{ 
           updateOnContentResize: true,
           updateOnImageLoad: true,
           updateOnSelectorChange: "ul",
           updateOnSelectorChange: "ul li",
        } 
     });
  
     $("#expandYear ul").mCustomScrollbar("update");
  </code></pre>
  
  <p>Library custom scrollbar I use: <a href="http://manos.malihu.gr/jquery-custom-content-scroller/" rel="nofollow noreferrer">http://manos.malihu.gr/jquery-custom-content-scroller</a></p>
  
  <p>Thanks!</p>