wip.

demo/Ursa.Demo/Pages/NavMenuDemo.axaml

@@ -11,10 +11,10 @@
     x:CompileBindings="True"
     x:DataType="vm:NavMenuDemoViewModel"
     mc:Ignorable="d">
+    <ScrollViewer>
         <StackPanel>
             <TextBlock Text="{ReflectionBinding #menu2.SelectedItem.Header}"></TextBlock>
             <u:NavMenu Name="menu2">
-
                 <u:NavMenuItem Header="Menu 1">
                     <u:NavMenuItem.Icon>
                         <Rectangle
@@ -48,9 +48,9 @@
             <u:NavMenu
                 Name="menu"
                 ItemsSource="{Binding MenuItems}"
-            HeaderBinding="{Binding Header}"
+                HeaderBinding="{Binding}"
                 SubMenuBinding="{Binding  Children}"
                 IconBinding="{Binding Header}"/>
         </StackPanel>
-    
+    </ScrollViewer>
 </UserControl>

demo/Ursa.Demo/ViewModels/NavMenuDemoViewModel.cs

@@ -13,7 +13,12 @@ public class NavMenuDemoViewModel: ObservableObject
     {
         new MenuItem { Header = "Introduction" , Children =
         {
-            new MenuItem() { Header = "Getting Started" },
+            new MenuItem() { Header = "Getting Started", Children =
+            {
+                new MenuItem() { Header = "Code of Conduct" },
+                new MenuItem() { Header = "How to Contribute" },
+                new MenuItem() { Header = "Development Workflow" },
+            }},
             new MenuItem() { Header = "Design Principles" },
             new MenuItem() { Header = "Contributing", Children =
             {

src/Ursa.Themes.Semi/Controls/NavMenu.axaml

@@ -7,7 +7,9 @@
         <Setter Property="Grid.IsSharedSizeScope" Value="True" />
         <Setter Property="Template">
             <ControlTemplate TargetType="u:NavMenu">
+                <ScrollViewer HorizontalScrollBarVisibility="Disabled" VerticalScrollBarVisibility="Auto">
                     <ItemsPresenter ItemsPanel="{TemplateBinding ItemsPanel}" />
+                </ScrollViewer>
             </ControlTemplate>
         </Setter>
     </ControlTheme>
@@ -15,19 +17,22 @@
     <ControlTheme x:Key="{x:Type u:NavMenuItem}" TargetType="u:NavMenuItem">
         <Setter Property="Template">
             <ControlTemplate TargetType="u:NavMenuItem">
-                <Grid RowDefinitions="Auto, *">
+                <Grid RowDefinitions="Auto, *" Background="{TemplateBinding Background}">
                     <Grid Grid.Row="0">
                         <Grid.ColumnDefinitions>
                             <ColumnDefinition Width="Auto" SharedSizeGroup="Icon" />
-                            <ColumnDefinition Width="*" />
+                            <ColumnDefinition Width="*" SharedSizeGroup="Header" />
+                            <ColumnDefinition Width="Auto" SharedSizeGroup="Expander" />
                         </Grid.ColumnDefinitions>
                         <ContentPresenter
                             HorizontalAlignment="Left"
-                            Background="Aqua"
+                            Padding="8"
+                            Background="Transparent"
                             Content="{TemplateBinding Icon}" />
                         <ContentPresenter
                             Grid.Column="1"
-                            Background="LightYellow"
+                            Padding="0 8"
+                            Background="Transparent"
                             Content="{TemplateBinding Header}" />
                     </Grid>
                     <ItemsPresenter
@@ -38,5 +43,9 @@
                 </Grid>
             </ControlTemplate>
         </Setter>
+        
+        <Style Selector="^:selected">
+            <Setter Property="Background" Value="{DynamicResource NavigationMenuItemSelectedBackground}" />
+        </Style>
     </ControlTheme>
 </ResourceDictionary>

src/Ursa/Controls/NavMenu/NavMenuItem.cs

@@ -11,6 +11,12 @@ using Avalonia.VisualTree;
 
 namespace Ursa.Controls;
 
+/// <summary>
+/// Navigation Menu Item
+/// <para>Note:</para>
+/// <para>collapsed: Entire menu is collapsed, only first level icon is displayed. Submenus are in popup. </para>
+/// <para>closed: When menu is not in collapsed mode, represents whether submenu is hidden. </para>
+/// </summary>
 [PseudoClasses(PC_Highlighted, PC_Collapsed, PC_Closed, PC_FirstLevel, PC_Selector)]
 public class NavMenuItem: HeaderedSelectingItemsControl
 {
@@ -145,7 +151,10 @@ public class NavMenuItem: HeaderedSelectingItemsControl
     protected override void OnPointerPressed(PointerPressedEventArgs e)
     {
         base.OnPointerPressed(e);
+        if (this.ItemCount == 0)
+        {
             SelectItem(this);
+        }
         Command?.Execute(CommandParameter);
         e.Handled = true;
     }
@@ -165,6 +174,14 @@ public class NavMenuItem: HeaderedSelectingItemsControl
         if (this.Parent is NavMenuItem menuItem)
         {
             menuItem.SelectItem(item);
+            var items = menuItem.LogicalChildren.OfType<NavMenuItem>();
+            foreach (var child in items)
+            {
+                if (child != this)
+                {
+                    child.ClearSelection();
+                }
+            }
         }
         else if (this.Parent is NavMenu menu)
         {