OutlookBar with TreeView | Infragistics Forums

The OutlookBar is like a tabcontrol in that the only content that is shown is that of the selected item. So when the first group is selected, the Content properties (e.g. Content & ContentTemplate) of the ContentPresenter within the control gets set to that first group's Content and ContentTemplate properties. Actually this is done in the templates that are then bound to the SelectedGroupContent(Template(Selector)) properties exposed on the control which are updated as the SelectedGroup changes. When that happens that ContentPresenter uses the DataTemplate from the ContentTemplate to create an instance of the element to be displayed. When you selected the 2nd group, the Content properties of that same ContentPresenter are set to the second group's Content and ContentTemplate properties. When that happens the elements created for the first group are released. When you then select the first group again, the process starts over and the ContentPresenter creates a new element from the DataTemplate you supplied for the ContentTemplate which is why you see the nodes as collapsed - because it is a different instance of a treeview. Note, this is the same exact behavior you get if you switch this to a tab control. e.g.

<TabControl
    HorizontalAlignment="Left"
    Width="250"
    ItemsSource="{Binding RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=Window}, Path=NavigationMenuItems}"
    ScrollViewer.CanContentScroll="True">
 <TabControl.Resources>
  <DataTemplate x:Key="ItemTemplate">
   <TreeView Margin="0"
                BorderThickness="0"
                HorizontalContentAlignment="Stretch"
                VerticalContentAlignment="Stretch"
                Background="#767676"
                ItemsSource="{Binding}">
    <TreeView.ItemTemplate>
     <HierarchicalDataTemplate ItemsSource="{Binding NavigationMenuItemChildren}">
      <StackPanel Orientation="Horizontal" ToolTip="{Binding ToolTip}">
       <TextBlock Text="{Binding Header}"/>
      </StackPanel>
     </HierarchicalDataTemplate>
    </TreeView.ItemTemplate>
   </TreeView>
  </DataTemplate>
  <Style TargetType="{x:Type TabItem}">
   <Setter Property="Content" Value="{Binding NavigationMenuItems}"/>
   <Setter Property="ContentTemplate" Value="{StaticResource ItemTemplate}"/>
   <Setter Property="Header" Value="{Binding Path=Header}"/>
   <Setter Property="ToolTip" Value="{Binding Path=ToolTip}"/>
  </Style>
 </TabControl.Resources>
</TabControl>