I just noticed some strange behaviour of WPF's TreeView. I added both ItemContainerStyle to bind to "IsSelected" of my ViewModel and an ItemsTemplated for custom display of my data. But now the user cannot change the selected node anymore. For testing purposes I created a similar UI using ListView and Expander. This version works as excepted. Any tips why TreeView does fail?

 <TreeView ItemsSource="{Binding ElementName=frame, Path=list}">
        <TreeView.ItemContainerStyle>
            <Style TargetType="{x:Type TreeViewItem}" >
                <Setter Property="IsSelected" Value="{Binding Mode=TwoWay, Path=IsSelected}"/>
            </Style>
        </TreeView.ItemContainerStyle>
        <TreeView.ItemTemplate>
            <HierarchicalDataTemplate>
                <TreeViewItem Header="{Binding}">
                    <TextBlock Text="{Binding Path= Item.SomeData}"/>
                </TreeViewItem>
            </HierarchicalDataTemplate>
        </TreeView.ItemTemplate>
    </TreeView>