title: How to show loading icon on RadComboBox Selected Index Changed
body: <p>I have implemented this demo from telerik 
  <a href="http://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/multiplecomboboxes/defaultcs.aspx" rel="nofollow">http://demos.telerik.com/aspnet-ajax/combobox/examples/functionality/multiplecomboboxes/defaultcs.aspx</a></p>
  
  <p>I just want the country combobox show Loading icon as in above demo here is my code</p>
  
  <pre><code>&lt;telerik:RadComboBox ID="RoomCategoryID" runat="server" Height="200px" Width="200px" EmptyMessage="Select Category"  
  EnableLoadOnDemand="True" MarkFirstMatch="True" CausesValidation="False" AutoPostBack="True" OnSelectedIndexChanged="DropDownList2_SelectedIndexChanged"
                           ShowMoreResultsBox="True" EnableVirtualScrolling="True"&gt;
                           &lt;/telerik:RadComboBox&gt;
  </code></pre>
  
  <p>and the other combobox code is </p>
  
  <pre><code>&lt;telerik:RadComboBox ID="SubCategoryID" runat="server" Height="200px" Width="200px" EmptyMessage="Select Sub Category"
      EnableLoadOnDemand="True" MarkFirstMatch="True" CausesValidation="False" 
                               ShowMoreResultsBox="True" EnableVirtualScrolling="True"/&gt;
  </code></pre>
  
  <p>and the event is </p>
  
  <pre><code>protected void DropDownList2_SelectedIndexChanged(object o, Telerik.Web.UI.RadComboBoxSelectedIndexChangedEventArgs e)
          {
      //This event takes lots of time to load That's why I want Loading icon
      }
  </code></pre>
  
  <p>and ajax setting code is </p>
  
  <pre><code>&lt;telerik:RadAjaxManager ID="RadAjaxManager1" runat="server" DefaultLoadingPanelID="RadAjaxLoadingPanel1"&gt;
                  &lt;AjaxSettings&gt;
       &lt;telerik:AjaxSetting AjaxControlID="RoomCategoryID"&gt;
                  &lt;UpdatedControls&gt;
                      &lt;telerik:AjaxUpdatedControl ControlID="SubCategoryID"/&gt;
                      &lt;telerik:AjaxUpdatedControl ControlID="pnlRoomExtra"/&gt;
                  &lt;/UpdatedControls&gt;
              &lt;/telerik:AjaxSetting&gt;
                        &lt;/AjaxSettings&gt;
                        &lt;/telerik:RadAjaxManager&gt;
                &lt;telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server" /&gt;
  </code></pre>
  
  <p>In my case it is not continent and country they are RoomCategory and RoomSubCategory</p>