sanitizer section not recognized by web.Config under system.web

I have been following along several examples that supposedly work but mine keeps giving me the red line highlight.  Here is my web.config:

<?xml version="1.0"?><configuration><configSections><sectionGroup name="system.web"><section name="sanitizer" requirePermission="false" type="AjaxControlToolkit.Sanitizer.ProviderSanitizerSection, AjaxControlToolkit"/></sectionGroup></configSections><connectionStrings><add name="MyConn" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\BCCS_Data.mdf;Integrated Security=True"/></connectionStrings><system.web><compilation debug="true" targetFramework="4.0"/><pages><controls><add tagPrefix="ajaxToolkit" assembly="AjaxControlToolkit" namespace="AjaxControlToolkit" /></controls></pages><sanitizer defaultProvider="AntiXssSanitizerProvider"> !-- this is what goes bad --><providers><add name="AntiXssSanitizerProvider"
             type="AjaxControlToolkit.Sanitizer.AntiXssSanitizerProvider"></add></providers></sanitizer><assemblies><add assembly="System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/><add assembly="System.Web.Extensions.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/><add assembly="System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/></assemblies><!--
            The <authentication> section enables configuration 
            of the security authentication mode used by 
            ASP.NET to identify an incoming user. 
        --><authentication mode="Windows"/><!--
            The <customErrors> section enables configuration 
            of what to do if/when an unhandled error occurs 
            during the execution of a request. Specifically, 
            it enables developers to configure html error pages 
            to be displayed in place of a error stack trace.<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm"><error statusCode="403" redirect="NoAccess.htm" /><error statusCode="404" redirect="FileNotFound.htm" /></customErrors>
        --><!--<pages controlRenderingCompatibilityVersion="3.5" clientIDMode="AutoID"/>--></system.web><!--
    For a description of web.config changes see http://go.microsoft.com/fwlink/?LinkId=235367.

    The following attributes can be set on the <httpRuntime> tag.<system.Web><httpRuntime targetFramework="4.5" /></system.Web>
  --></configuration>

Says this <sanitizer> element is invalid, it expects other element names.