Hi, I have a ListBox bound to an ObservableCollection with an ItemTemplate that contains another ListBox. First of all, I tried to get the last selected item of all the listboxes (either the parent and the inner ones) from my MainWindowViewModel this way: public object SelectedItem { get { return this.selectedItem; } set { this.selectedItem = value; base.NotifyPropertyChanged("SelectedItem"); } } So, for example, in the DataTemplate of the items of the parent ListBox I've got this: <ListBox ItemsSource="{Binding Tails}" SelectedItem="{Binding Path=DataContext.SelectedItem, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}"/> The problem now, is that when I select an item from the parent ListBox and then an item from a child listbox, I get this: http://i40.tinypic.com/j7bvig.jpg As you can see, two items are selected at the same time. How can I solve that? Thanks in advance.