Controles Telerik requer Script Manager

Fui adicionar um RadDatePicker em meu WEB Form e quando rodo dá esse erro. Que Script Manager é esse que se está pedindo?


Server Error in '/' Application.
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The control with ID 'RadDatePicker1' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: The control with ID 'RadDatePicker1' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[InvalidOperationException: The control with ID 'RadDatePicker1' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.]
Telerik.Web.UI.ScriptRegistrar.GetScriptManager(Control control) +316
Telerik.Web.UI.RadWebControl.get_ScriptManager() +46
Telerik.Web.UI.RadWebControl.RegisterScriptControl() +51
Telerik.Web.UI.RadWebControl.ControlPreRender() +33
Telerik.Web.UI.RadDatePicker.ControlPreRender() +31
Telerik.Web.UI.RadWebControl.OnPreRender(EventArgs e) +47
System.Web.UI.Control.PreRenderRecursiveInternal() +103
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Control.PreRenderRecursiveInternal() +175
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496