I have Filter by Columns turned on in RadGrid, and the UI displays the text input boxes and filter button. But clicking the filter button doesn't show the filter menu, and the JS console is showing an error: $find is not defined. I'm guessing I'm missing a JavaScript library. This is an inherited app that I'm trying to repair, so if there's any guidance as to which script files I need or how to pull them in through an installer, it would be greatly appreciated.
<telerik:radgrid runat="server" ID="rgConfirmed" AllowFilteringByColumn="True" AllowPaging="True" AllowSorting="True" ShowStatusBar="True"
DataSourceID="DropShipOrders" GridLines="None" PageSize="20" Skin="Telerik" AutoGenerateColumns="False">