RadAjaxLoadingPanel causes Sys.WebForms.PageRequestManagerParserErrorException:

[Ben]

Hello,

I have a very simple page that has one <asp:label> and one radgrid.  Everything works great and I have no issues.  Now, I'm trying to add a LoadingPanel so the user gets some feedback while the grid is resorting/grouping/filtering, etc.  I added the following from the demo:

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server">
    <AjaxSettings>
        <telerik:AjaxSetting AjaxControlID="ClaimsGrid">
            <UpdatedControls>
                <telerik:AjaxUpdatedControl ControlID="ClaimsGrid" LoadingPanelID="RadAjaxLoadingPanel1" />
            </UpdatedControls>
        </telerik:AjaxSetting>
    </AjaxSettings>
</telerik:RadAjaxManager>
<telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server" />

But now when I perform certain actions, I get the following error:

Microsoft JScript runtime error: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near '<td>30</td><td>504.0'.

Thanks,
Ben

[Maria Ilieva]

Hello Ben,

Please review the answer provided in the support ticket you have opened with us for the same issue. It will be better to continue our communication in the official support ticket for best tracking the issue.

Best wishes,
Maria Ilieva
the Telerik team