AJAX WITH VISUAL STUDIO 2012

Hi Friends,

I installed  ajax  toolkit with (visualstudio 2012 ulitmate) asp.net 4.5 since second day, I download ajax toolkit and installed add reference , when trying to drag ajax control to webform its not moving, even add following line

<%@RegisterAssembly="AjaxControlToolkit"Namespace="AjaxControlToolkit.HTMLEditor"TagPrefix="cc1"%>

but when trying to add following tag show green line error under <ajaxtoolkit:

<ajaxtoolkit:calendarextender ID="Calendarextender

please help me.

thank you.

regards,

asad