title: ValidatorCalloutExtender not working in Asp.net Ajax
body: <p>I have a RadioButtonList with Yes and No Option.Upon clicking the Yes button,Textbox1 and TextBox2 will be displayed and clicking No button Textbox3 and Textbox4 will be displayed.All the above the textboxes have ValidatorCalloutExtender.Upon clicking the  Submit Button, the ValidatorCalloutExtender is not popup.Can any please help me..</p>
  
  <p>Here is the code sample:</p>
  
  <p></p>
  
  <pre><code>                            &lt;asp:RequiredFieldValidator ID="rfvENo" runat="server" ControlToValidate="txt1"
                                  Display="None" ErrorMessage="Please Enter ENo!" ValidationGroup="Agent" /&gt;
                              &lt;cc1:ValidatorCalloutExtender ID="ValidatorCalloutExtender10" runat="server" Enabled="True"
                                  TargetControlID="rfvENo"&gt;
                              &lt;/cc1:ValidatorCalloutExtender&gt;
  </code></pre>