Can't add AjaxToolkit Control to User Control

Question

I have a simple user control and I want to add an AjaxToolkit control to it. The one I want is the ModalPopupExtender, but the same thing happens no matter which AjaxToolkit control I choose. When I drag and drop the control onto the Source page instead of appending the @Register line and the tags I get a whole bunch of xml type code starting with

<soap-env:envelope soap-env:encodingstyle="........

I have even tried manualy typing in an @Register line adding ToolkitScriptManager line and then a ModalPopupExtender and no joy.

Any help appreciated.

Answer 1

Praveen Correct only happened in UserControl (ascx file)... I tried fixing first by doing a clean. This did not help. I then closed VS2010 and cleared the ReflectedSchemas directory and this fixed the issue.