AjaxUpdatedControl Problem

[Yo]

Hi,
      I have try to setup my AjaxUpdated Control as below code:  
      And got the error  as attached image but it's running OK if i just click "continuous".
      Any idea what's the problem is ? Thanks 

      <telerik:RadAjaxManager ID="RadAjaxManager1" runat="server" OnAjaxRequest="RadAjaxManager1_AjaxRequest" DefaultLoadingPanelID="LoadingPanel1">
            <AjaxSettings>
                <telerik:AjaxSetting AjaxControlID="RadAjaxManager1">
                    <UpdatedControls>
                        <telerik:AjaxUpdatedControl ControlID ="MRibbonBar" />
                    </UpdatedControls>
                </telerik:AjaxSetting>
                <telerik:AjaxSetting AjaxControlID="MRibbonBar">
                    <UpdatedControls>
                        <telerik:AjaxUpdatedControl ControlID ="MasterGrid" />
                    </UpdatedControls>
                </telerik:AjaxSetting>
            </AjaxSettings>
        </telerik:RadAjaxManager>

[Radoslav]

Hi Yo,

Based on the provided information it is hard to say what is causing the described issue. Could you please post the full aspx page markup with the related code behind? Thus we will be able to gather more details about your scenario and provide you with more to-the-point answer.

Looking forward for your reply.

Regards,
Radoslav
Telerik