"Not a registered script control" error when using RadMenu inside RadComboBox and setting MinFilterLength

[Daniel]

Hello,

I am trying to embed a RadMenu inside a RadComboBox. Everything works fine until I try to configure the combobox to request items only after at least three characters have been entered into the filter. Once I set the EnableAutomaticLoadOnDemand to "true" I get the error attached.

My code is below. Please advise on possible steps to resolve this issue.

<telerik:RadComboBox ID="RadComboBox4" runat="server" Width="590px" Height="140px"
    Filter="Contains" ShowToggleImage="False" EmptyMessage="Fund..." MinFilterLength="3" EnableAutomaticLoadOnDemand="True"
    DataSourceID="SqlDataSource1" DataTextField="Name" DataValueField="FundID"
    OnItemDataBound="RadComboBox4_ItemDataBound" >
    <ItemTemplate>
        <div style="float: left">
            <asp:Label ID="Label1" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "Name") %>'></asp:Label>
        </div>
        <div style="float: right">
            <telerik:RadMenu ID="RadMenu1" runat="server" EnableRoundedCorners="true" EnableShadows="true" >
                <Items>
                    <telerik:RadMenuItem Text="Fund ID">
                        <GroupSettings ExpandDirection="Right"></GroupSettings>
                        <Items>
                            <telerik:RadMenuItem Text="About US">
                            </telerik:RadMenuItem>
                            <telerik:RadMenuItem Text="Strategic Plan">
                            </telerik:RadMenuItem>
                            <telerik:RadMenuItem Text="Executive Bios">
                            </telerik:RadMenuItem>
                            <telerik:RadMenuItem Text="Contact Us">
                            </telerik:RadMenuItem>
                        </Items>
                    </telerik:RadMenuItem>
                </Items>
            </telerik:RadMenu>
        </div>
        <br /><br />
    </ItemTemplate>
</telerik:RadComboBox>

[Dimitar Terziev]

Hi,

The usage of load on demand and server controls as templates is not supported scenario. RadMenu is a server control by nature and it needs to be initialized on the server, but when the RadComboBox performs a request for items a callback to the server is made which is quite different than the standard post-back. More information about this difference could be found in the following forum thread here.

Kind regards,
Dimitar Terziev
the Telerik team