JavaScript error is thrown on the page, when a classic DropDownList is clicked in application running with .NET 3.5, debug mode.

Error message:

"Uncaught Sys.ParameterCountException: Sys.ParameterCountException: Parameter count mismatch."

Steps to reproduce:
1. Run this code with .NET 3.5 and <compilation debug="true">
        <asp:ScriptManager ID="sm" runat="server" ScriptMode="Debug">
        </asp:ScriptManager>
        <telerik:RadFormDecorator runat="server" EnableRoundedCorners="true" DecoratedControls="All" />
        <asp:DropDownList runat="server">
            <asp:ListItem Text="text1" />
            <asp:ListItem Text="text2" />
        </asp:DropDownList>

2. Click the drop-down button.

Result: A JS error is thrown.

This happens because under .NET 3.5, in the .debug.js version of the MS AJAX scripts, the Function$emptyMethod() method RadFormDecorator uses has parameter validation and throws errors when you pass any arguments. This is not present in release and seems to not be present in newer versions of .NET