app.xaml

      <Style
           BasedOn="{StaticResource MetroListView}"
           TargetType="{x:Type ListView}">
        <Setter Property="ScrollViewer.CanContentScroll" Value="True" />
        <Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="True" />
        <Setter Property="VirtualizingStackPanel.IsVirtualizing" Value="True" />
        <Setter Property="VirtualizingStackPanel.VirtualizationMode" Value="Recycling" />
      </Style>