title: Adding AjaxControlToolkit stops postback
body: <p>I have a basic form with two textboxes and a drop-down value. The page works okay normally, but as soon as I add a reference to AjaxControlToolkit (which I'd like to use for the Calendar control), the PostBack stops working. The page is submitted, but eventually times out and never refreshes.<br />
  All I do to create this behaviour is add:<br />
      <code>&lt;%@ Register TagPrefix="asp" Namespace="AjaxControlToolkit" Assembly="AjaxControlToolkit"%&gt;</code><br />
  after the Page directive, and then add:<br />
       <code>&lt;asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="Server" /&gt;</code><br />
  in the page body. I am NOT adding any reference to the Calendar (or any AJAX) controls at this stage.
  Why won't the page refresh? Thanks.</p>