<TreeView Grid.Row="2" x:Name="TestMethodTree"
MouseDoubleClick="TreeView_MouseDoubleClick"
ItemsSource="{Binding Source={StaticResource OutcomeGroupViewSource}, Path=Groups}"
ItemTemplate="{StaticResource OutcomeTemplate}">
<i:Interaction.Behaviors>
<local:BindableSelectedItemBehavior SelectedItem="{Binding SelectedItem, Mode=TwoWay}" />
</i:Interaction.Behaviors>
</TreeView>