[WPF] ListView: SelectedItems returns always one element

Hi,

I using ListView:

DataContext="{StaticResource DomainDataViewModel}" ItemsSource="{Binding SampleStatus}" IsSynchronizedWithCurrentItem="True" Width="727" Height="50">

  ItemWidth="{Binding (ListView.View).ItemWidth, RelativeSource={RelativeSource AncestorType=ListView}}"

  MinWidth="{Binding ItemWidth, RelativeSource={RelativeSource Self}}"

  ItemHeight="{Binding (ListView.View).ItemHeight, RelativeSource={RelativeSource AncestorType=ListView}}" />

I see 8 elements (checkbox + label), I select 2 or more element, but in code behind if I would get selected item with:

chkListViewSampleStatus.SelectedItems

It returns always one element.

Why?

Thanks.