insert managed chrome when extend client area is enabled and hint flag is set.

samples/ControlCatalog/Pages/WindowCustomizationsPage.xaml

@@ -8,6 +8,7 @@
     <CheckBox Content="Extend Client Area to Decorations" IsChecked="{Binding ExtendClientAreaEnabled}" />
     <CheckBox Content="Titlebar" IsChecked="{Binding SystemTitleBarEnabled}" />
     <CheckBox Content="System Chrome Buttons" IsChecked="{Binding SystemChromeButtonsEnabled}" />
+    <CheckBox Content="Managed Chrome Buttons" IsChecked="{Binding ManagedChromeButtonsEnabled}" />
     <Slider Minimum="-1" Maximum="200" Value="{Binding TitleBarHeight}" />
     <ComboBox x:Name="TransparencyLevels" SelectedIndex="{Binding TransparencyLevel}">
       <ComboBoxItem>None</ComboBoxItem>

samples/ControlCatalog/ViewModels/MainWindowViewModel.cs

@@ -65,7 +65,7 @@ namespace ControlCatalog.ViewModels
                 WindowState.FullScreen,
             };
 
-            this.WhenAnyValue(x => x.SystemChromeButtonsEnabled, x => x.SystemTitleBarEnabled)
+            this.WhenAnyValue(x => x.SystemChromeButtonsEnabled, x=>x.ManagedChromeButtonsEnabled, x => x.SystemTitleBarEnabled)
                 .Subscribe(x =>
                 {
                     ChromeHints = ExtendClientAreaChromeHints.NoChrome;
@@ -76,6 +76,11 @@ namespace ControlCatalog.ViewModels
                     }
 
                     if(x.Item2)
+                    {
+                        ChromeHints |= ExtendClientAreaChromeHints.ManagedChromeButtons;
+                    }
+
+                    if(x.Item3)
                     {
                         ChromeHints |= ExtendClientAreaChromeHints.SystemTitleBar;
                     }
@@ -127,6 +132,15 @@ namespace ControlCatalog.ViewModels
             set { this.RaiseAndSetIfChanged(ref _systemChromeButtonsEnabled, value); }
         }
 
+        private bool _managedChromeButtonsEnabled;
+
+        public bool ManagedChromeButtonsEnabled
+        {
+            get { return _managedChromeButtonsEnabled; }
+            set { this.RaiseAndSetIfChanged(ref _managedChromeButtonsEnabled, value); }
+        }
+
+
         private double _titleBarHeight;
 
         public double TitleBarHeight

src/Avalonia.Controls/Window.cs

@@ -4,6 +4,7 @@ using System.ComponentModel;
 using System.Linq;
 using System.Reactive.Linq;
 using System.Threading.Tasks;
+using Avalonia.Controls.Chrome;
 using Avalonia.Controls.Platform;
 using Avalonia.Data;
 using Avalonia.Input;
@@ -69,7 +70,8 @@ namespace Avalonia.Controls
     /// </summary>
     public class Window : WindowBase, IStyleable, IFocusScope, ILayoutRoot
     {
-        private readonly List<(Window child, bool isDialog)> _children = new List<(Window, bool)>();
+        private readonly List<(Window child, bool isDialog)> _children = new List<(Window, bool)>();        
+        private CaptionButtons _managedCaptions;
 
         private bool _isExtendedIntoWindowDecorations;
 
@@ -203,7 +205,15 @@ namespace Avalonia.Controls
                 (w, e) => { if (w.PlatformImpl != null) w.PlatformImpl.SetExtendClientAreaToDecorationsHint((bool)e.NewValue); });
 
             ExtendClientAreaChromeHintsProperty.Changed.AddClassHandler<Window>(
-                (w, e) => { if (w.PlatformImpl != null) w.PlatformImpl.SetExtendClientAreaChromeHints((ExtendClientAreaChromeHints)e.NewValue); });
+                (w, e) =>
+                {
+                    if (w.PlatformImpl != null)
+                    {
+                        w.PlatformImpl.SetExtendClientAreaChromeHints((ExtendClientAreaChromeHints)e.NewValue);
+                    }
+
+                    w.HandleChromeHintsChanged((ExtendClientAreaChromeHints)e.NewValue);
+                });
 
             ExtendClientAreaTitleBarHeightHintProperty.Changed.AddClassHandler<Window>(
                 (w, e) => { if (w.PlatformImpl != null) w.PlatformImpl.SetExtendClientAreaTitleBarHeightHint((double)e.NewValue); });
@@ -897,6 +907,26 @@ namespace Avalonia.Controls
             base.HandleResized(clientSize);
         }
 
+        private void HandleChromeHintsChanged (ExtendClientAreaChromeHints hints)
+        {
+            if(hints.HasFlag(ExtendClientAreaChromeHints.ManagedChromeButtons))
+            {
+                if(_managedCaptions == null)
+                {
+                    _managedCaptions = new CaptionButtons(this);
+                }
+
+                _managedCaptions.Attach();
+            }
+            else
+            {
+                if(_managedCaptions != null)
+                {
+                    _managedCaptions.Detach();
+                }
+            }
+        }
+
         /// <summary>
         /// Raises the <see cref="Closing"/> event.
         /// </summary>