Seems like this is the DNN issue with the new AspNetAjaxLibrary.
If you use older AJAXControlToolKit then DNN is ok. But the work arround I have given in my previous post, it should do the trick (but golden rule "Never modify the core", unless you can change it by your module core, dynamically, during runtime).
Further investigation has given me more clear picture about current DNN. I have looked at the DNN AJAX framework library, which is adding "ScriptManager" and found
'''''''''''''''''''''''''''''''''''
Public Shared Sub RegisterScriptManager()
If Not IsEnabled() Then
HttpContext.Current.Items.Add("System.Web.UI.ScriptManager", True)
End If
End Sub
'''''''''''''''''''''''''''''''
which is clearly telling me, current DNN does not support new AspNetAjaxLibrary (System.Web.Ajax.dll, AjaxControlToolkit.dll version 3.0.31106.0), as currently it is getting reference from ASPNETAJAXExt3.5 (System.Web.Extensions, Version=3.5.0.0)
Not too sure what is the best way to over come this issue, for new AspNetAjaxLibrary "RegisterScriptManager" method should do following
HttpContext.Current.Items.Add("System.Web.UI.AjaxScriptManager", true);
HttpContext.Current.Items.Add("AjaxControlToolkit.ToolkitScriptManager", true);
Possible solutions:
1. Change "RegisterScriptManager" method
2. Create your old method and use it in your module
3. From your module dynamically remove "System.Web.UI.ScriptManager" and add "System.Web.UI.AjaxScriptManager" or "AjaxControlToolkit.ToolkitScriptManager"
Really like to hear from DNN.