How do I add advanced filter on xceed datagrid?

Question

I followed the documentation from xceed and used parameters like AllowAdvancedFilter="True" and

<xceed:DataGridControl.View> <xceed:TableflowView AdvancedFilterMode="Always"/> </xceed:DataGridControl.View>

but its not showing the advanced filter dialog box on the column.

in .xaml file

 <xceed:DataGridControl Grid.Row="2" x:Name="DataItemsControl" AutoCreateColumns="false"  Margin="5"  >
 
     <xceed:DataGridControl.Columns >
         <xceed:Column FieldName="IsActive" Title="Active?" />
         <xceed:Column FieldName="Name" Title="Prospect Name" AllowAdvancedFilter="True" ReadOnly="True"/>
        
     </xceed:DataGridControl.Columns>
     <xceed:DataGridControl.View>
         <xceed:TableflowView AdvancedFilterMode="Always"/>
     </xceed:DataGridControl.View>
     
 </xceed:DataGridControl>

and i am populating the table like this in xaml.cs

this.DataItemsControl.ItemsSource = this.ViewModel.PortfolioProspects.ToReactiveList(); 

it does not show me the dialog box for the advanced filter. Has anyone able to display advanced filter dialog on xceed?