<px:PXGrid ID="gridNS" runat="server" SkinID="DetailsInTab" Width="100%" Height="150px" Caption="Mailings" AdjustPageSize="Auto" AllowPaging="True" DataSourceID="ds">

    <AutoSize Enabled="True" />

    <AutoCallBack Target="gridNR" Command="Refresh" />

    <Levels>

        <px:PXGridLevel DataMember=“NotificationSources" DataKeyNames="SourceID,SetupID">

            <Columns>

            ...

            </Columns>

        </px:PXGridLevel>

    </Levels>

</px:PXGrid>