Merge branch 'master' into fixes/Issue_6263

packages/Avalonia/Avalonia.csproj

@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-      <PackageReference Include="Avalonia.BuildServices" Version="0.0.12" />
+      <PackageReference Include="Avalonia.BuildServices" Version="0.0.15" />
       <ProjectReference Include="../../src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj" />
       <ProjectReference Include="../../src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj">
         <PrivateAssets>all</PrivateAssets>

samples/ControlCatalog/Pages/ColorPickerPage.xaml

@@ -103,7 +103,8 @@
                    HsvColor="{Binding HsvColor, ElementName=ColorSpectrum1}" />-->
       <ColorPreviewer Grid.Row="8"
                       IsAccentColorsVisible="False"
-                      HsvColor="{Binding HsvColor, ElementName=ColorSpectrum1}" />
+                      HsvColor="{Binding HsvColor, ElementName=ColorSpectrum1}"
+                      Margin="0,2,0,0" />
     </Grid>
   </Grid>
 </UserControl>

src/Avalonia.Base/Diagnostics/AppliedStyle.cs

@@ -0,0 +1,18 @@
+using Avalonia.Styling;
+
+namespace Avalonia.Diagnostics
+{
+    public class AppliedStyle
+    {
+        private readonly IStyleInstance _instance;
+
+        internal AppliedStyle(IStyleInstance instance)
+        {
+            _instance = instance;
+        }
+
+        public bool HasActivator => _instance.HasActivator;
+        public bool IsActive => _instance.IsActive;
+        public StyleBase Style => (StyleBase)_instance.Source;
+    }
+}

src/Avalonia.Base/Diagnostics/StyleDiagnostics.cs

@@ -11,9 +11,9 @@ namespace Avalonia.Diagnostics
         /// <summary>
         /// Currently applied styles.
         /// </summary>
-        public IReadOnlyList<IStyleInstance> AppliedStyles { get; }
+        public IReadOnlyList<AppliedStyle> AppliedStyles { get; }
 
-        public StyleDiagnostics(IReadOnlyList<IStyleInstance> appliedStyles)
+        public StyleDiagnostics(IReadOnlyList<AppliedStyle> appliedStyles)
         {
             AppliedStyles = appliedStyles;
         }

src/Avalonia.Base/Input/AccessKeyHandler.cs

@@ -141,9 +141,11 @@ namespace Avalonia.Input
 
                 if (MainMenu == null || !MainMenu.IsOpen)
                 {
+                    var focusManager = FocusManager.GetFocusManager(e.Source as IInputElement);
+                    
                     // TODO: Use FocusScopes to store the current element and restore it when context menu is closed.
                     // Save currently focused input element.
-                    _restoreFocusElement = FocusManager.Instance?.Current;
+                    _restoreFocusElement = focusManager?.GetFocusedElement();
 
                     // When Alt is pressed without a main menu, or with a closed main menu, show
                     // access key markers in the window (i.e. "_File").

src/Avalonia.Base/Input/FocusManager.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Runtime.CompilerServices;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Input
@@ -10,6 +11,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Manages focus for the application.
     /// </summary>
+    [PrivateApi]
     public class FocusManager : IFocusManager
     {
         /// <summary>
@@ -29,15 +31,12 @@ namespace Avalonia.Input
                 RoutingStrategies.Tunnel);
         }
 
-        /// <summary>
-        /// Gets the instance of the <see cref="IFocusManager"/>.
-        /// </summary>
-        public static IFocusManager? Instance => AvaloniaLocator.Current.GetService<IFocusManager>();
+        private IInputElement? Current => KeyboardDevice.Instance?.FocusedElement;
 
         /// <summary>
         /// Gets the currently focused <see cref="IInputElement"/>.
         /// </summary>
-        public IInputElement? Current => KeyboardDevice.Instance?.FocusedElement;
+        public IInputElement? GetFocusedElement() => Current;
 
         /// <summary>
         /// Gets the current focus scope.
@@ -54,7 +53,7 @@ namespace Avalonia.Input
         /// <param name="control">The control to focus.</param>
         /// <param name="method">The method by which focus was changed.</param>
         /// <param name="keyModifiers">Any key modifiers active at the time of focus.</param>
-        public void Focus(
+        public bool Focus(
             IInputElement? control, 
             NavigationMethod method = NavigationMethod.Unspecified,
             KeyModifiers keyModifiers = KeyModifiers.None)
@@ -67,7 +66,7 @@ namespace Avalonia.Input
                 if (scope != null)
                 {
                     Scope = scope;
-                    SetFocusedElement(scope, control, method, keyModifiers);
+                    return SetFocusedElement(scope, control, method, keyModifiers);
                 }
             }
             else if (Current != null)
@@ -79,28 +78,29 @@ namespace Avalonia.Input
                         _focusScopes.TryGetValue(scope, out var element) &&
                         element != null)
                     {
-                        Focus(element, method);
-                        return;
+                        return Focus(element, method);
                     }
                 }
 
                 if (Scope is object)
                 {
                     // Couldn't find a focus scope, clear focus.
-                    SetFocusedElement(Scope, null);
+                    return SetFocusedElement(Scope, null);
                 }
             }
+
+            return false;
         }
 
-        public IInputElement? GetFocusedElement(IInputElement e)
+        public void ClearFocus()
         {
-            if (e is IFocusScope scope)
-            {
-                _focusScopes.TryGetValue(scope, out var result);
-                return result;
-            }
+            Focus(null);
+        }
 
-            return null;
+        public IInputElement? GetFocusedElement(IFocusScope scope)
+        {
+            _focusScopes.TryGetValue(scope, out var result);
+            return result;
         }
 
         /// <summary>
@@ -114,7 +114,7 @@ namespace Avalonia.Input
         /// If the specified scope is the current <see cref="Scope"/> then the keyboard focus
         /// will change.
         /// </remarks>
-        public void SetFocusedElement(
+        public bool SetFocusedElement(
             IFocusScope scope,
             IInputElement? element,
             NavigationMethod method = NavigationMethod.Unspecified,
@@ -124,7 +124,7 @@ namespace Avalonia.Input
 
             if (element is not null && !CanFocus(element))
             {
-                return;
+                return false;
             }
 
             if (_focusScopes.TryGetValue(scope, out var existingElement))
@@ -144,6 +144,8 @@ namespace Avalonia.Input
             {
                 KeyboardDevice.Instance?.SetFocusedElement(element, method, keyModifiers);
             }
+
+            return true;
         }
 
         /// <summary>
@@ -185,6 +187,20 @@ namespace Avalonia.Input
 
         public static bool GetIsFocusScope(IInputElement e) => e is IFocusScope;
 
+        /// <summary>
+        /// Public API customers should use TopLevel.GetTopLevel(control).FocusManager.
+        /// But since we have split projects, we can't access TopLevel from Avalonia.Base.
+        /// That's why we need this helper method instead.
+        /// </summary>
+        internal static FocusManager? GetFocusManager(IInputElement? element)
+        {
+            // Element might not be a visual, and not attached to the root.
+            // But IFocusManager is always expected to be a FocusManager. 
+            return (FocusManager?)((element as Visual)?.VisualRoot as IInputRoot)?.FocusManager
+                   // In our unit tests some elements might not have a root. Remove when we migrate to headless tests.
+                ?? (FocusManager?)AvaloniaLocator.Current.GetService<IFocusManager>();
+        }
+        
         /// <summary>
         /// Checks if the specified element can be focused.
         /// </summary>
@@ -237,7 +253,7 @@ namespace Avalonia.Input
                 {
                     if (element is IInputElement inputElement && CanFocus(inputElement))
                     {
-                        Instance?.Focus(inputElement, NavigationMethod.Pointer, ev.KeyModifiers);
+                        inputElement.Focus(NavigationMethod.Pointer, ev.KeyModifiers);
 
                         break;
                     }

src/Avalonia.Base/Input/IFocusManager.cs

@@ -11,40 +11,12 @@ namespace Avalonia.Input
         /// <summary>
         /// Gets the currently focused <see cref="IInputElement"/>.
         /// </summary>
-        IInputElement? Current { get; }
+        IInputElement? GetFocusedElement();
 
         /// <summary>
-        /// Gets the current focus scope.
+        /// Clears currently focused element.
         /// </summary>
-        IFocusScope? Scope { get; }
-
-        /// <summary>
-        /// Focuses a control.
-        /// </summary>
-        /// <param name="control">The control to focus.</param>
-        /// <param name="method">The method by which focus was changed.</param>
-        /// <param name="keyModifiers">Any key modifiers active at the time of focus.</param>
-        void Focus(
-            IInputElement? control,
-            NavigationMethod method = NavigationMethod.Unspecified,
-            KeyModifiers keyModifiers = KeyModifiers.None);
-
-        /// <summary>
-        /// Notifies the focus manager of a change in focus scope.
-        /// </summary>
-        /// <param name="scope">The new focus scope.</param>
-        /// <remarks>
-        /// This should not be called by client code. It is called by an <see cref="IFocusScope"/>
-        /// when it activates, e.g. when a Window is activated.
-        /// </remarks>
-        void SetFocusScope(IFocusScope scope);
-
-        /// <summary>
-        /// Notifies the focus manager that a focus scope has been removed.
-        /// </summary>
-        /// <param name="scope">The focus scope to be removed.</param>
-        /// This should not be called by client code. It is called by an <see cref="IFocusScope"/>
-        /// when it deactivates or closes, e.g. when a Window is closed.
-        void RemoveFocusScope(IFocusScope scope);
+        [Unstable("This API might be removed in 11.x minor updates. Please consider focusing another element instead of removing focus at all for better UX.")]
+        void ClearFocus();
     }
 }

src/Avalonia.Base/Input/IFocusScope.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IFocusScope
     {
     }

src/Avalonia.Base/Input/IInputElement.cs

@@ -119,7 +119,9 @@ namespace Avalonia.Input
         /// <summary>
         /// Focuses the control.
         /// </summary>
-        void Focus();
+        /// <param name="method">The method by which focus was changed.</param>
+        /// <param name="keyModifiers">Any key modifiers active at the time of focus.</param>
+        bool Focus(NavigationMethod method = NavigationMethod.Unspecified, KeyModifiers keyModifiers = KeyModifiers.None);
 
         /// <summary>
         /// Gets the key bindings for the element.

src/Avalonia.Base/Input/IInputRoot.cs

@@ -18,6 +18,14 @@ namespace Avalonia.Input
         /// </summary>
         IKeyboardNavigationHandler KeyboardNavigationHandler { get; }
 
+        /// <summary>
+        /// Gets focus manager of the root.
+        /// </summary>
+        /// <remarks>
+        /// Focus manager can be null only if application wasn't initialized yet.
+        /// </remarks>
+        IFocusManager? FocusManager { get; }
+        
         /// <summary>
         /// Gets or sets the input element that the pointer is currently over.
         /// </summary>

src/Avalonia.Base/Input/IKeyboardDevice.cs

@@ -44,13 +44,7 @@ namespace Avalonia.Input
     }
 
     [NotClientImplementable]
-    public interface IKeyboardDevice : IInputDevice, INotifyPropertyChanged
+    public interface IKeyboardDevice : IInputDevice
     {
-        IInputElement? FocusedElement { get; }
-
-        void SetFocusedElement(
-            IInputElement? element, 
-            NavigationMethod method,
-            KeyModifiers modifiers);
     }
 }

src/Avalonia.Base/Input/InputElement.cs

@@ -458,9 +458,10 @@ namespace Avalonia.Input
                 SetAndRaise(IsEffectivelyEnabledProperty, ref _isEffectivelyEnabled, value);
                 PseudoClasses.Set(":disabled", !value);
 
-                if (!IsEffectivelyEnabled && FocusManager.Instance?.Current == this)
+                if (!IsEffectivelyEnabled && FocusManager.GetFocusManager(this) is {} focusManager
+                    && Equals(focusManager.GetFocusedElement(), this))
                 {
-                    FocusManager.Instance?.Focus(null);
+                    focusManager.ClearFocus();
                 }
             }
         }
@@ -491,12 +492,10 @@ namespace Avalonia.Input
         public GestureRecognizerCollection GestureRecognizers
             => _gestureRecognizers ?? (_gestureRecognizers = new GestureRecognizerCollection(this));
 
-        /// <summary>
-        /// Focuses the control.
-        /// </summary>
-        public void Focus()
+        /// <inheritdoc />
+        public bool Focus(NavigationMethod method = NavigationMethod.Unspecified, KeyModifiers keyModifiers = KeyModifiers.None)
         {
-            FocusManager.Instance?.Focus(this);
+            return FocusManager.GetFocusManager(this)?.Focus(this, method, keyModifiers) ?? false; 
         }
 
         /// <inheritdoc/>
@@ -506,7 +505,7 @@ namespace Avalonia.Input
 
             if (IsFocused)
             {
-                FocusManager.Instance?.Focus(null);
+                FocusManager.GetFocusManager(this)?.ClearFocus();
             }
         }
 
@@ -649,7 +648,7 @@ namespace Avalonia.Input
             }
             else if (change.Property == IsVisibleProperty && !change.GetNewValue<bool>() && IsFocused)
             {
-                FocusManager.Instance?.Focus(null);
+                FocusManager.GetFocusManager(this)?.ClearFocus();
             }
         }
 

src/Avalonia.Base/Input/KeyboardDevice.cs

@@ -3,9 +3,11 @@ using System.Runtime.CompilerServices;
 using Avalonia.Input.Raw;
 using Avalonia.Input.TextInput;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
+    [PrivateApi]
     public class KeyboardDevice : IKeyboardDevice, INotifyPropertyChanged
     {
         private IInputElement? _focusedElement;
@@ -13,7 +15,7 @@ namespace Avalonia.Input
 
         public event PropertyChangedEventHandler? PropertyChanged;
 
-        public static IKeyboardDevice? Instance => AvaloniaLocator.Current.GetService<IKeyboardDevice>();
+        internal static KeyboardDevice? Instance => AvaloniaLocator.Current.GetService<IKeyboardDevice>() as KeyboardDevice;
 
         public IInputManager? InputManager => AvaloniaLocator.Current.GetService<IInputManager>();
 

src/Avalonia.Base/Input/KeyboardNavigationHandler.cs

@@ -88,7 +88,7 @@ namespace Avalonia.Input
                 var method = direction == NavigationDirection.Next ||
                              direction == NavigationDirection.Previous ?
                              NavigationMethod.Tab : NavigationMethod.Directional;
-                FocusManager.Instance?.Focus(next, method, keyModifiers);
+                next.Focus(method, keyModifiers);
             }
         }
 
@@ -99,7 +99,7 @@ namespace Avalonia.Input
         /// <param name="e">The event args.</param>
         protected virtual void OnKeyDown(object? sender, KeyEventArgs e)
         {
-            var current = FocusManager.Instance?.Current;
+            var current = FocusManager.GetFocusManager(e.Source as IInputElement)?.GetFocusedElement();
 
             if (current != null && e.Key == Key.Tab)
             {

src/Avalonia.Base/Input/MouseDevice.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using Avalonia.Reactive;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 using Avalonia.Platform;
 using Avalonia.Utilities;
 #pragma warning disable CS0618
@@ -11,6 +12,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Represents a mouse device.
     /// </summary>
+    [PrivateApi]
     public class MouseDevice : IMouseDevice, IDisposable
     {
         private int _clickCount;

src/Avalonia.Base/Input/Navigation/TabNavigation.cs

@@ -190,9 +190,11 @@ namespace Avalonia.Input.Navigation
         private static IInputElement? FocusedElement(IInputElement? e)
         {
             // Focus delegation is enabled only if keyboard focus is outside the container
-            if (e != null && !e.IsKeyboardFocusWithin)
+            if (e != null && !e.IsKeyboardFocusWithin && e is IFocusScope scope)
             {
-                var focusedElement = (FocusManager.Instance as FocusManager)?.GetFocusedElement(e);
+                var focusManager = FocusManager.GetFocusManager(e);
+
+                var focusedElement = focusManager?.GetFocusedElement(scope);
                 if (focusedElement != null)
                 {
                     if (!IsFocusScope(e))

src/Avalonia.Base/Input/PenDevice.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 using Avalonia.Platform;
 #pragma warning disable CS0618
 
@@ -11,6 +12,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Represents a pen/stylus device.
     /// </summary>
+    [PrivateApi]
     public class PenDevice : IPenDevice, IDisposable
     {
         private readonly Dictionary<long, Pointer> _pointers = new();

src/Avalonia.Base/Input/TouchDevice.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 using Avalonia.Platform;
 #pragma warning disable CS0618
 
@@ -14,6 +15,7 @@ namespace Avalonia.Input
     /// <remarks>
     /// This class is supposed to be used on per-toplevel basis, don't use a shared one
     /// </remarks>
+    [PrivateApi]
     public class TouchDevice : IPointerDevice, IDisposable
     {
         private readonly Dictionary<long, Pointer> _pointers = new Dictionary<long, Pointer>();

src/Avalonia.Base/Media/Color.cs

@@ -478,7 +478,6 @@ namespace Avalonia.Media
         /// <returns>The HSL equivalent color.</returns>
         public HslColor ToHsl()
         {
-            // Don't use the HslColor(Color) constructor to avoid an extra HslColor
             return Color.ToHsl(R, G, B, A);
         }
 
@@ -488,7 +487,6 @@ namespace Avalonia.Media
         /// <returns>The HSV equivalent color.</returns>
         public HsvColor ToHsv()
         {
-            // Don't use the HsvColor(Color) constructor to avoid an extra HsvColor
             return Color.ToHsv(R, G, B, A);
         }
 
@@ -517,21 +515,6 @@ namespace Avalonia.Media
             }
         }
 
-        /// <summary>
-        /// Converts the given RGB color to its HSL color equivalent.
-        /// </summary>
-        /// <param name="color">The color in the RGB color model.</param>
-        /// <returns>A new <see cref="HslColor"/> equivalent to the given RGBA values.</returns>
-        public static HslColor ToHsl(Color color)
-        {
-            // Normalize RGBA components into the 0..1 range
-            return Color.ToHsl(
-                (byteToDouble * color.R),
-                (byteToDouble * color.G),
-                (byteToDouble * color.B),
-                (byteToDouble * color.A));
-        }
-
         /// <summary>
         /// Converts the given RGBA color component values to their HSL color equivalent.
         /// </summary>
@@ -606,21 +589,6 @@ namespace Avalonia.Media
             return new HslColor(a, 60 * h1, saturation, lightness, clampValues: false);
         }
 
-        /// <summary>
-        /// Converts the given RGB color to its HSV color equivalent.
-        /// </summary>
-        /// <param name="color">The color in the RGB color model.</param>
-        /// <returns>A new <see cref="HsvColor"/> equivalent to the given RGBA values.</returns>
-        public static HsvColor ToHsv(Color color)
-        {
-            // Normalize RGBA components into the 0..1 range
-            return Color.ToHsv(
-                (byteToDouble * color.R),
-                (byteToDouble * color.G),
-                (byteToDouble * color.B),
-                (byteToDouble * color.A));
-        }
-
         /// <summary>
         /// Converts the given RGBA color component values to their HSV color equivalent.
         /// </summary>

src/Avalonia.Base/Media/HslColor.cs

@@ -90,7 +90,7 @@ namespace Avalonia.Media
         /// <param name="color">The RGB color to convert to HSL.</param>
         public HslColor(Color color)
         {
-            var hsl = Color.ToHsl(color);
+            var hsl = color.ToHsl();
 
             A = hsl.A;
             H = hsl.H;
@@ -165,10 +165,18 @@ namespace Avalonia.Media
         /// <returns>The RGB equivalent color.</returns>
         public Color ToRgb()
         {
-            // Use the by-component conversion method directly for performance
             return HslColor.ToRgb(H, S, L, A);
         }
 
+        /// <summary>
+        /// Returns the HSV color model equivalent of this HSL color.
+        /// </summary>
+        /// <returns>The HSV equivalent color.</returns>
+        public HsvColor ToHsv()
+        {
+            return HslColor.ToHsv(H, S, L, A);
+        }
+
         /// <inheritdoc/>
         public override string ToString()
         {
@@ -349,16 +357,6 @@ namespace Avalonia.Media
             return new HslColor(1.0, h, s, l);
         }
 
-        /// <summary>
-        /// Converts the given HSL color to its RGB color equivalent.
-        /// </summary>
-        /// <param name="hslColor">The color in the HSL color model.</param>
-        /// <returns>A new RGB <see cref="Color"/> equivalent to the given HSLA values.</returns>
-        public static Color ToRgb(HslColor hslColor)
-        {
-            return HslColor.ToRgb(hslColor.H, hslColor.S, hslColor.L, hslColor.A);
-        }
-
         /// <summary>
         /// Converts the given HSLA color component values to their RGB color equivalent.
         /// </summary>
@@ -442,13 +440,67 @@ namespace Avalonia.Media
                 b1 = x;
             }
 
-            return Color.FromArgb(
+            return new Color(
                 (byte)Math.Round(255 * alpha),
                 (byte)Math.Round(255 * (r1 + m)),
                 (byte)Math.Round(255 * (g1 + m)),
                 (byte)Math.Round(255 * (b1 + m)));
         }
 
+        /// <summary>
+        /// Converts the given HSLA color component values to their HSV color equivalent.
+        /// </summary>
+        /// <param name="hue">The Hue component in the HSL color model in the range from 0..360.</param>
+        /// <param name="saturation">The Saturation component in the HSL color model in the range from 0..1.</param>
+        /// <param name="lightness">The Lightness component in the HSL color model in the range from 0..1.</param>
+        /// <param name="alpha">The Alpha component in the range from 0..1.</param>
+        /// <returns>A new <see cref="HsvColor"/> equivalent to the given HSLA values.</returns>
+        public static HsvColor ToHsv(
+            double hue,
+            double saturation,
+            double lightness,
+            double alpha = 1.0)
+        {
+            // We want the hue to be between 0 and 359,
+            // so we first ensure that that's the case.
+            while (hue >= 360.0)
+            {
+                hue -= 360.0;
+            }
+
+            while (hue < 0.0)
+            {
+                hue += 360.0;
+            }
+
+            // We similarly clamp saturation, lightness and alpha between 0 and 1.
+            saturation = saturation < 0.0 ? 0.0 : saturation;
+            saturation = saturation > 1.0 ? 1.0 : saturation;
+
+            lightness = lightness < 0.0 ? 0.0 : lightness;
+            lightness = lightness > 1.0 ? 1.0 : lightness;
+
+            alpha = alpha < 0.0 ? 0.0 : alpha;
+            alpha = alpha > 1.0 ? 1.0 : alpha;
+
+            // The conversion algorithm is from the below link
+            // https://en.wikipedia.org/wiki/HSL_and_HSV#Interconversion
+
+            double s;
+            double v = lightness + (saturation * Math.Min(lightness, 1.0 - lightness));
+
+            if (v <= 0)
+            {
+                s = 0;
+            }
+            else
+            {
+                s = 2.0 * (1.0 - (lightness / v));
+            }
+
+            return new HsvColor(alpha, hue, s, v);
+        }
+
         /// <summary>
         /// Indicates whether the values of two specified <see cref="HslColor"/> objects are equal.
         /// </summary>

src/Avalonia.Base/Media/HsvColor.cs

@@ -90,7 +90,7 @@ namespace Avalonia.Media
         /// <param name="color">The RGB color to convert to HSV.</param>
         public HsvColor(Color color)
         {
-            var hsv = Color.ToHsv(color);
+            var hsv = color.ToHsv();
 
             A = hsv.A;
             H = hsv.H;
@@ -195,10 +195,18 @@ namespace Avalonia.Media
         /// <returns>The RGB equivalent color.</returns>
         public Color ToRgb()
         {
-            // Use the by-component conversion method directly for performance
             return HsvColor.ToRgb(H, S, V, A);
         }
 
+        /// <summary>
+        /// Returns the HSL color model equivalent of this HSV color.
+        /// </summary>
+        /// <returns>The HSL equivalent color.</returns>
+        public HslColor ToHsl()
+        {
+            return HsvColor.ToHsl(H, S, V, A);
+        }
+
         /// <inheritdoc/>
         public override string ToString()
         {
@@ -379,16 +387,6 @@ namespace Avalonia.Media
             return new HsvColor(1.0, h, s, v);
         }
 
-        /// <summary>
-        /// Converts the given HSV color to its RGB color equivalent.
-        /// </summary>
-        /// <param name="hsvColor">The color in the HSV color model.</param>
-        /// <returns>A new RGB <see cref="Color"/> equivalent to the given HSVA values.</returns>
-        public static Color ToRgb(HsvColor hsvColor)
-        {
-            return HsvColor.ToRgb(hsvColor.H, hsvColor.S, hsvColor.V, hsvColor.A);
-        }
-
         /// <summary>
         /// Converts the given HSVA color component values to their RGB color equivalent.
         /// </summary>
@@ -520,13 +518,67 @@ namespace Avalonia.Media
                     break;
             }
 
-            return Color.FromArgb(
+            return new Color(
                 (byte)Math.Round(alpha * 255),
                 (byte)Math.Round(r * 255),
                 (byte)Math.Round(g * 255),
                 (byte)Math.Round(b * 255));
         }
 
+        /// <summary>
+        /// Converts the given HSVA color component values to their HSL color equivalent.
+        /// </summary>
+        /// <param name="hue">The Hue component in the HSV color model in the range from 0..360.</param>
+        /// <param name="saturation">The Saturation component in the HSV color model in the range from 0..1.</param>
+        /// <param name="value">The Value component in the HSV color model in the range from 0..1.</param>
+        /// <param name="alpha">The Alpha component in the range from 0..1.</param>
+        /// <returns>A new <see cref="HslColor"/> equivalent to the given HSVA values.</returns>
+        public static HslColor ToHsl(
+            double hue,
+            double saturation,
+            double value,
+            double alpha = 1.0)
+        {
+            // We want the hue to be between 0 and 359,
+            // so we first ensure that that's the case.
+            while (hue >= 360.0)
+            {
+                hue -= 360.0;
+            }
+
+            while (hue < 0.0)
+            {
+                hue += 360.0;
+            }
+
+            // We similarly clamp saturation, value and alpha between 0 and 1.
+            saturation = saturation < 0.0 ? 0.0 : saturation;
+            saturation = saturation > 1.0 ? 1.0 : saturation;
+
+            value = value < 0.0 ? 0.0 : value;
+            value = value > 1.0 ? 1.0 : value;
+
+            alpha = alpha < 0.0 ? 0.0 : alpha;
+            alpha = alpha > 1.0 ? 1.0 : alpha;
+
+            // The conversion algorithm is from the below link
+            // https://en.wikipedia.org/wiki/HSL_and_HSV#Interconversion
+
+            double s;
+            double l = value * (1.0 - (saturation / 2.0));
+
+            if (l <= 0 || l >= 1)
+            {
+                s = 0.0;
+            }
+            else
+            {
+                s = (value - l) / Math.Min(l, 1.0 - l);
+            }
+
+            return new HslColor(alpha, hue, s, l);
+        }
+
         /// <summary>
         /// Indicates whether the values of two specified <see cref="HsvColor"/> objects are equal.
         /// </summary>

src/Avalonia.Base/StyledElement.cs

@@ -420,12 +420,12 @@ namespace Avalonia
 
         internal StyleDiagnostics GetStyleDiagnosticsInternal()
         {
-            var styles = new List<IStyleInstance>();
+            var styles = new List<AppliedStyle>();
 
             foreach (var frame in GetValueStore().Frames)
             {
                 if (frame is IStyleInstance style)
-                    styles.Add(style);
+                    styles.Add(new(style));
             }
 
             return new StyleDiagnostics(styles);

src/Avalonia.Base/Styling/Activators/IStyleActivator.cs

@@ -15,8 +15,7 @@ namespace Avalonia.Styling.Activators
     /// - The activation state can be re-evaluated at any time by calling <see cref="GetIsActive"/>
     /// - No error or completion messages
     /// </remarks>
-    [Unstable]
-    public interface IStyleActivator : IDisposable
+    internal interface IStyleActivator : IDisposable
     {
         /// <summary>
         /// Gets a value indicating whether the style is subscribed.

src/Avalonia.Base/Styling/Activators/IStyleActivatorSink.cs

@@ -5,8 +5,7 @@ namespace Avalonia.Styling.Activators
     /// <summary>
     /// Receives notifications from an <see cref="IStyleActivator"/>.
     /// </summary>
-    [Unstable]
-    public interface IStyleActivatorSink
+    internal interface IStyleActivatorSink
     {
         /// <summary>
         /// Called when the subscribed activator value changes.

src/Avalonia.Base/Styling/ChildSelector.cs

@@ -19,13 +19,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => _parent.InTemplate;
+        internal override bool InTemplate => _parent.InTemplate;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => true;
+        internal override bool IsCombinator => true;
 
         /// <inheritdoc/>
-        public override Type? TargetType => null;
+        internal override Type? TargetType => null;
 
         public override string ToString(Style? owner)
         {
@@ -37,7 +37,7 @@ namespace Avalonia.Styling
             return _selectorString;
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             var controlParent = ((ILogical)control).LogicalParent;
 
@@ -64,7 +64,7 @@ namespace Avalonia.Styling
             }
         }
 
-        protected override Selector? MovePrevious() => null;
-        protected override Selector? MovePreviousOrParent() => _parent;
+        private protected override Selector? MovePrevious() => null;
+        private protected override Selector? MovePreviousOrParent() => _parent;
     }
 }

src/Avalonia.Base/Styling/DescendentSelector.cs

@@ -17,13 +17,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool IsCombinator => true;
+        internal override bool IsCombinator => true;
 
         /// <inheritdoc/>
-        public override bool InTemplate => _parent.InTemplate;
+        internal override bool InTemplate => _parent.InTemplate;
 
         /// <inheritdoc/>
-        public override Type? TargetType => null;
+        internal override Type? TargetType => null;
 
         public override string ToString(Style? owner)
         {
@@ -35,7 +35,7 @@ namespace Avalonia.Styling
             return _selectorString;
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             var c = (ILogical)control;
             var descendantMatches = new OrActivatorBuilder();
@@ -69,7 +69,7 @@ namespace Avalonia.Styling
             }
         }
 
-        protected override Selector? MovePrevious() => null;
-        protected override Selector? MovePreviousOrParent() => _parent;
+        private protected override Selector? MovePrevious() => null;
+        private protected override Selector? MovePreviousOrParent() => _parent;
     }
 }

src/Avalonia.Base/Styling/ISetter.cs

@@ -1,24 +0,0 @@
-using System;
-using Avalonia.Metadata;
-
-namespace Avalonia.Styling
-{
-    /// <summary>
-    /// Represents a setter for a <see cref="Style"/>.
-    /// </summary>
-    [NotClientImplementable]
-    public interface ISetter
-    {
-        /// <summary>
-        /// Instances a setter on a control.
-        /// </summary>
-        /// <param name="styleInstance">The style which contains the setter.</param>
-        /// <param name="target">The control.</param>
-        /// <returns>An <see cref="ISetterInstance"/>.</returns>
-        /// <remarks>
-        /// This method should return an <see cref="ISetterInstance"/> which can be used to apply
-        /// the setter to the specified control.
-        /// </remarks>
-        ISetterInstance Instance(IStyleInstance styleInstance, StyledElement target);
-    }
-}

src/Avalonia.Base/Styling/ISetterInstance.cs

@@ -3,7 +3,7 @@
 namespace Avalonia.Styling
 {
     /// <summary>
-    /// Represents an <see cref="ISetter"/> that has been instanced on a control.
+    /// Represents a <see cref="Setter"/> that has been instanced on a control.
     /// </summary>
     [Unstable]
     public interface ISetterInstance

src/Avalonia.Base/Styling/ISetterValue.cs

@@ -3,13 +3,13 @@
 namespace Avalonia.Styling
 {
     /// <summary>
-    /// Customizes the behavior of a class when added as a value to an <see cref="ISetter"/>.
+    /// Customizes the behavior of a class when added as a value to a <see cref="SetterBase"/>.
     /// </summary>
     public interface ISetterValue
     {
         /// <summary>
         /// Notifies that the object has been added as a setter value.
         /// </summary>
-        void Initialize(ISetter setter);
+        void Initialize(SetterBase setter);
     }
 }

src/Avalonia.Base/Styling/IStyleInstance.cs

@@ -5,8 +5,7 @@ namespace Avalonia.Styling
     /// <summary>
     /// Represents a <see cref="Style"/> that has been instanced on a control.
     /// </summary>
-    [Unstable]
-    public interface IStyleInstance
+    internal interface IStyleInstance
     {
         /// <summary>
         /// Gets the source style.

src/Avalonia.Base/Styling/NestingSelector.cs

@@ -7,13 +7,13 @@ namespace Avalonia.Styling
     /// </summary>
     internal class NestingSelector : Selector
     {
-        public override bool InTemplate => false;
-        public override bool IsCombinator => false;
-        public override Type? TargetType => null;
+        internal override bool InTemplate => false;
+        internal override bool IsCombinator => false;
+        internal override Type? TargetType => null;
 
         public override string ToString(Style? owner) => owner?.Parent?.ToString() ?? "^";
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             if (parent is Style s && s.Selector is not null)
             {
@@ -32,7 +32,7 @@ namespace Avalonia.Styling
                 "Nesting selector was specified but cannot determine parent selector.");
         }
 
-        protected override Selector? MovePrevious() => null;
-        protected override Selector? MovePreviousOrParent() => null;
+        private protected override Selector? MovePrevious() => null;
+        private protected override Selector? MovePreviousOrParent() => null;
     }
 }

src/Avalonia.Base/Styling/NotSelector.cs

@@ -26,13 +26,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => _argument.InTemplate;
+        internal override bool InTemplate => _argument.InTemplate;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
         /// <inheritdoc/>
-        public override Type? TargetType => _previous?.TargetType;
+        internal override Type? TargetType => _previous?.TargetType;
 
         /// <inheritdoc/>
         public override string ToString(Style? owner)
@@ -45,7 +45,7 @@ namespace Avalonia.Styling
             return _selectorString;
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             var innerResult = _argument.Match(control, parent, subscribe);
 
@@ -66,7 +66,7 @@ namespace Avalonia.Styling
             }
         }
 
-        protected override Selector? MovePrevious() => _previous;
-        protected override Selector? MovePreviousOrParent() => _previous;
+        private protected override Selector? MovePrevious() => _previous;
+        private protected override Selector? MovePreviousOrParent() => _previous;
     }
 }

src/Avalonia.Base/Styling/NthChildSelector.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Styling
     /// <remarks>
     /// Element indices are 1-based.
     /// </remarks>
-    public class NthChildSelector : Selector
+    internal class NthChildSelector : Selector
     {
         private const string NthChildSelectorName = "nth-child";
         private const string NthLastChildSelectorName = "nth-last-child";
@@ -39,16 +39,16 @@ namespace Avalonia.Styling
 
         }
 
-        public override bool InTemplate => _previous?.InTemplate ?? false;
+        internal override bool InTemplate => _previous?.InTemplate ?? false;
 
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
-        public override Type? TargetType => _previous?.TargetType;
+        internal override Type? TargetType => _previous?.TargetType;
 
         public int Step { get; }
         public int Offset { get; }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             if (!(control is ILogical logical))
             {
@@ -103,8 +103,8 @@ namespace Avalonia.Styling
             return match ? SelectorMatch.AlwaysThisInstance : SelectorMatch.NeverThisInstance;
         }
 
-        protected override Selector? MovePrevious() => _previous;
-        protected override Selector? MovePreviousOrParent() => _previous;
+        private protected override Selector? MovePrevious() => _previous;
+        private protected override Selector? MovePreviousOrParent() => _previous;
 
         public override string ToString(Style? owner)
         {

src/Avalonia.Base/Styling/NthLastChildSelector.cs

@@ -8,7 +8,7 @@ namespace Avalonia.Styling
     /// <remarks>
     /// Element indices are 1-based.
     /// </remarks>
-    public class NthLastChildSelector : NthChildSelector
+    internal class NthLastChildSelector : NthChildSelector
     {
         /// <summary>
         /// Creates an instance of <see cref="NthLastChildSelector"/>

src/Avalonia.Base/Styling/OrSelector.cs

@@ -36,13 +36,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => false;
+        internal override bool InTemplate => false;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
         /// <inheritdoc/>
-        public override Type? TargetType => _targetType ??= EvaluateTargetType();
+        internal override Type? TargetType => _targetType ??= EvaluateTargetType();
 
         /// <inheritdoc/>
         public override string ToString(Style? owner)
@@ -55,7 +55,7 @@ namespace Avalonia.Styling
             return _selectorString;
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             var activators = new OrActivatorBuilder();
             var neverThisInstance = false;
@@ -94,8 +94,8 @@ namespace Avalonia.Styling
             }
         }
 
-        protected override Selector? MovePrevious() => null;
-        protected override Selector? MovePreviousOrParent() => null;
+        private protected override Selector? MovePrevious() => null;
+        private protected override Selector? MovePreviousOrParent() => null;
 
         internal override void ValidateNestingSelector(bool inControlTheme)
         {

src/Avalonia.Base/Styling/PropertyEqualsSelector.cs

@@ -28,13 +28,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => _previous?.InTemplate ?? false;
+        internal override bool InTemplate => _previous?.InTemplate ?? false;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
         /// <inheritdoc/>
-        public override Type? TargetType => _previous?.TargetType;
+        internal override Type? TargetType => _previous?.TargetType;
 
         /// <inheritdoc/>
         public override string ToString(Style? owner)
@@ -73,7 +73,7 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             if (subscribe)
             {
@@ -88,8 +88,8 @@ namespace Avalonia.Styling
             
         }
 
-        protected override Selector? MovePrevious() => _previous;
-        protected override Selector? MovePreviousOrParent() => _previous;
+        private protected override Selector? MovePrevious() => _previous;
+        private protected override Selector? MovePreviousOrParent() => _previous;
 
         [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = TrimmingMessages.TypeConvertionSupressWarningMessage)]
         [UnconditionalSuppressMessage("Trimming", "IL2067", Justification = TrimmingMessages.TypeConvertionSupressWarningMessage)]

src/Avalonia.Base/Styling/Selector.cs

@@ -14,7 +14,7 @@ namespace Avalonia.Styling
         /// Gets a value indicating whether either this selector or a previous selector has moved
         /// into a template.
         /// </summary>
-        public abstract bool InTemplate { get; }
+        internal abstract bool InTemplate { get; }
 
         /// <summary>
         /// Gets a value indicating whether this selector is a combinator.
@@ -22,12 +22,12 @@ namespace Avalonia.Styling
         /// <remarks>
         /// A combinator is a selector such as Child or Descendent which links simple selectors.
         /// </remarks>
-        public abstract bool IsCombinator { get; }
+        internal abstract bool IsCombinator { get; }
 
         /// <summary>
         /// Gets the target type of the selector, if available.
         /// </summary>
-        public abstract Type? TargetType { get; }
+        internal abstract Type? TargetType { get; }
 
         /// <summary>
         /// Tries to match the selector with a control.
@@ -41,7 +41,7 @@ namespace Avalonia.Styling
         /// or simply return an immediate result.
         /// </param>
         /// <returns>A <see cref="SelectorMatch"/>.</returns>
-        public SelectorMatch Match(StyledElement control, IStyle? parent = null, bool subscribe = true)
+        internal SelectorMatch Match(StyledElement control, IStyle? parent = null, bool subscribe = true)
         {
             // First match the selector until a combinator is found. Selectors are stored from 
             // right-to-left, so MatchUntilCombinator reverses this order because the type selector
@@ -88,17 +88,17 @@ namespace Avalonia.Styling
         /// or simply return an immediate result.
         /// </param>
         /// <returns>A <see cref="SelectorMatch"/>.</returns>
-        protected abstract SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe);
+        private protected abstract SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe);
 
         /// <summary>
         /// Moves to the previous selector.
         /// </summary>
-        protected abstract Selector? MovePrevious();
+        private protected abstract Selector? MovePrevious();
 
         /// <summary>
         /// Moves to the previous selector or the parent selector.
         /// </summary>
-        protected abstract Selector? MovePreviousOrParent();
+        private protected abstract Selector? MovePreviousOrParent();
 
         internal virtual void ValidateNestingSelector(bool inControlTheme)
         {

src/Avalonia.Base/Styling/SelectorMatch.cs

@@ -8,7 +8,7 @@ namespace Avalonia.Styling
     /// <summary>
     /// Describes how a <see cref="SelectorMatch"/> matches a control and its type.
     /// </summary>
-    public enum SelectorMatchResult
+    internal enum SelectorMatchResult
     {
         /// <summary>
         /// The selector never matches this type.
@@ -43,7 +43,7 @@ namespace Avalonia.Styling
     /// A selector match describes whether and how a <see cref="Selector"/> matches a control, and
     /// in addition whether the selector can ever match a control of the same type.
     /// </remarks>
-    public readonly record struct SelectorMatch
+    internal readonly record struct SelectorMatch
     {
         /// <summary>
         /// A selector match with the result of <see cref="SelectorMatchResult.NeverThisType"/>.

src/Avalonia.Base/Styling/Setter.cs

@@ -14,7 +14,7 @@ namespace Avalonia.Styling
     /// A <see cref="Setter"/> is used to set a <see cref="AvaloniaProperty"/> value on a
     /// <see cref="AvaloniaObject"/> depending on a condition.
     /// </remarks>
-    public class Setter : ISetter, IValueEntry, ISetterInstance, IAnimationSetter
+    public class Setter : SetterBase, IValueEntry, ISetterInstance, IAnimationSetter
     {
         private object? _value;
         private DirectPropertySetterInstance? _direct;
@@ -66,7 +66,7 @@ namespace Avalonia.Styling
         void IValueEntry.Unsubscribe() { }
 
         [UnconditionalSuppressMessage("Trimming", "IL2026", Justification = TrimmingMessages.ImplicitTypeConvertionSupressWarningMessage)]
-        ISetterInstance ISetter.Instance(IStyleInstance instance, StyledElement target)
+        internal override ISetterInstance Instance(IStyleInstance instance, StyledElement target)
         {
             if (target is not AvaloniaObject ao)
                 throw new InvalidOperationException("Don't know how to instance a style on this type.");

src/Avalonia.Base/Styling/SetterBase.cs

@@ -0,0 +1,12 @@
+namespace Avalonia.Styling
+{
+    /// <summary>
+    /// Represents the base class for value setters.
+    /// </summary>
+    public abstract class SetterBase
+    {
+        internal abstract ISetterInstance Instance(
+            IStyleInstance styleInstance,
+            StyledElement target);
+    }
+}

src/Avalonia.Base/Styling/StyleBase.cs

@@ -16,7 +16,7 @@ namespace Avalonia.Styling
         private IResourceHost? _owner;
         private StyleChildren? _children;
         private IResourceDictionary? _resources;
-        private List<ISetter>? _setters;
+        private List<SetterBase>? _setters;
         private List<IAnimation>? _animations;
         private StyleInstance? _sharedInstance;
 
@@ -60,7 +60,7 @@ namespace Avalonia.Styling
             }
         }
 
-        public IList<ISetter> Setters => _setters ??= new List<ISetter>();
+        public IList<SetterBase> Setters => _setters ??= new();
         public IList<IAnimation> Animations => _animations ??= new List<IAnimation>();
 
         bool IResourceNode.HasResources => _resources?.Count > 0;
@@ -69,7 +69,7 @@ namespace Avalonia.Styling
         internal bool HasChildren => _children?.Count > 0;
         internal bool HasSettersOrAnimations => _setters?.Count > 0 || _animations?.Count > 0;
 
-        public void Add(ISetter setter) => Setters.Add(setter);
+        public void Add(SetterBase setter) => Setters.Add(setter);
         public void Add(IStyle style) => Children.Add(style);
 
         public event EventHandler? OwnerChanged;

src/Avalonia.Base/Styling/TemplateSelector.cs

@@ -18,13 +18,13 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => true;
+        internal override bool InTemplate => true;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => true;
+        internal override bool IsCombinator => true;
 
         /// <inheritdoc/>
-        public override Type? TargetType => null;
+        internal override Type? TargetType => null;
 
         public override string ToString(Style? owner)
         {
@@ -36,7 +36,7 @@ namespace Avalonia.Styling
             return _selectorString;
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             var templatedParent = control.TemplatedParent as StyledElement;
 
@@ -48,7 +48,7 @@ namespace Avalonia.Styling
             return _parent.Match(templatedParent, parent, subscribe);
         }
 
-        protected override Selector? MovePrevious() => null;
-        protected override Selector? MovePreviousOrParent() => _parent;
+        private protected override Selector? MovePrevious() => null;
+        private protected override Selector? MovePreviousOrParent() => _parent;
     }
 }

src/Avalonia.Base/Styling/TypeNameAndClassSelector.cs

@@ -58,7 +58,7 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        public override bool InTemplate => _previous?.InTemplate ?? false;
+        internal override bool InTemplate => _previous?.InTemplate ?? false;
 
         /// <summary>
         /// Gets the name of the control to match.
@@ -66,10 +66,10 @@ namespace Avalonia.Styling
         public string? Name { get; set; }
 
         /// <inheritdoc/>
-        public override Type? TargetType => _targetType ?? _previous?.TargetType;
+        internal override Type? TargetType => _targetType ?? _previous?.TargetType;
 
         /// <inheritdoc/>
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
         /// <summary>
         /// Whether the selector matches the concrete <see cref="TargetType"/> or any object which
@@ -89,7 +89,7 @@ namespace Avalonia.Styling
         }
 
         /// <inheritdoc/>
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle? parent, bool subscribe)
         {
             if (TargetType != null)
             {
@@ -134,8 +134,8 @@ namespace Avalonia.Styling
             return Name == null ? SelectorMatch.AlwaysThisType : SelectorMatch.AlwaysThisInstance;
         }
 
-        protected override Selector? MovePrevious() => _previous;
-        protected override Selector? MovePreviousOrParent() => _previous;
+        private protected override Selector? MovePrevious() => _previous;
+        private protected override Selector? MovePreviousOrParent() => _previous;
 
         private string BuildSelectorString(Style? owner)
         {

src/Avalonia.Controls.ColorPicker/ColorSlider/ColorSlider.Properties.cs

@@ -41,11 +41,19 @@ namespace Avalonia.Controls.Primitives
                 defaultBindingMode: BindingMode.TwoWay);
 
         /// <summary>
-        /// Defines the <see cref="IsAlphaMaxForced"/> property.
+        /// Defines the <see cref="IsAlphaVisible"/> property.
         /// </summary>
-        public static readonly StyledProperty<bool> IsAlphaMaxForcedProperty =
+        public static readonly StyledProperty<bool> IsAlphaVisibleProperty =
             AvaloniaProperty.Register<ColorSlider, bool>(
-                nameof(IsAlphaMaxForced),
+                nameof(IsAlphaVisible),
+                false);
+
+        /// <summary>
+        /// Defines the <see cref="IsPerceptive"/> property.
+        /// </summary>
+        public static readonly StyledProperty<bool> IsPerceptiveProperty =
+            AvaloniaProperty.Register<ColorSlider, bool>(
+                nameof(IsPerceptive),
                 true);
 
         /// <summary>
@@ -56,14 +64,6 @@ namespace Avalonia.Controls.Primitives
                 nameof(IsRoundingEnabled),
                 false);
 
-        /// <summary>
-        /// Defines the <see cref="IsSaturationValueMaxForced"/> property.
-        /// </summary>
-        public static readonly StyledProperty<bool> IsSaturationValueMaxForcedProperty =
-            AvaloniaProperty.Register<ColorSlider, bool>(
-                nameof(IsSaturationValueMaxForced),
-                true);
-
         /// <summary>
         /// Gets or sets the currently selected color in the RGB color model.
         /// </summary>
@@ -109,14 +109,41 @@ namespace Avalonia.Controls.Primitives
         }
 
         /// <summary>
-        /// Gets or sets a value indicating whether the alpha component is always forced to maximum for components
-        /// other than <see cref="ColorComponent"/>.
-        /// This ensures that the background is always visible and never transparent regardless of the actual color.
+        /// Gets or sets a value indicating whether the alpha component is visible and rendered.
+        /// When false, this ensures that the gradient is always visible and never transparent regardless of
+        /// the actual color. This property is ignored when the alpha component itself is being displayed.
+        /// </summary>
+        /// <remarks>
+        /// Setting to false means the alpha component is always forced to maximum for components other than
+        /// <see cref="ColorComponent"/> during rendering. This doesn't change the value of the alpha component
+        /// in the color – it is only for display.
+        /// </remarks>
+        public bool IsAlphaVisible
+        {
+            get => GetValue(IsAlphaVisibleProperty);
+            set => SetValue(IsAlphaVisibleProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the slider adapts rendering to improve user-perception
+        /// over exactness.
         /// </summary>
-        public bool IsAlphaMaxForced
+        /// <remarks>
+        /// When true in the HSVA color model, this ensures that the gradient is always visible and
+        /// never washed out regardless of the actual color. When true in the RGBA color model, this ensures
+        /// the gradient always appears as red, green or blue.
+        /// <br/><br/>
+        /// For example, with Hue in the HSVA color model, the Saturation and Value components are always forced
+        /// to maximum values during rendering. In the RGBA color model, all components other than
+        /// <see cref="ColorComponent"/> are forced to minimum values during rendering.
+        /// <br/><br/>
+        /// Note this property will only adjust components other than <see cref="ColorComponent"/> during rendering.
+        /// This also doesn't change the values of any components in the actual color – it is only for display.
+        /// </remarks>
+        public bool IsPerceptive
         {
-            get => GetValue(IsAlphaMaxForcedProperty);
-            set => SetValue(IsAlphaMaxForcedProperty, value);
+            get => GetValue(IsPerceptiveProperty);
+            set => SetValue(IsPerceptiveProperty, value);
         }
 
         /// <summary>
@@ -131,16 +158,5 @@ namespace Avalonia.Controls.Primitives
             get => GetValue(IsRoundingEnabledProperty);
             set => SetValue(IsRoundingEnabledProperty, value);
         }
-
-        /// <summary>
-        /// Gets or sets a value indicating whether the saturation and value components are always forced to maximum values
-        /// when using the HSVA color model. Only component values other than <see cref="ColorComponent"/> will be changed.
-        /// This ensures, for example, that the Hue background is always visible and never washed out regardless of the actual color.
-        /// </summary>
-        public bool IsSaturationValueMaxForced
-        {
-            get => GetValue(IsSaturationValueMaxForcedProperty);
-            set => SetValue(IsSaturationValueMaxForcedProperty, value);
-        }
     }
 }

src/Avalonia.Controls.ColorPicker/ColorSlider/ColorSlider.cs

@@ -52,8 +52,7 @@ namespace Avalonia.Controls.Primitives
             // This means under a certain alpha threshold, neither a white or black selector thumb
             // should be shown and instead the default slider thumb color should be used instead.
             if (Color.A < 128 &&
-                (IsAlphaMaxForced == false ||
-                 ColorComponent == ColorComponent.Alpha))
+                (IsAlphaVisible || ColorComponent == ColorComponent.Alpha))
             {
                 PseudoClasses.Set(pcDarkSelector, false);
                 PseudoClasses.Set(pcLightSelector, false);
@@ -64,11 +63,11 @@ namespace Avalonia.Controls.Primitives
 
                 if (ColorModel == ColorModel.Hsva)
                 {
-                    perceivedColor = GetEquivalentBackgroundColor(HsvColor).ToRgb();
+                    perceivedColor = GetPerceptiveBackgroundColor(HsvColor).ToRgb();
                 }
                 else
                 {
-                    perceivedColor = GetEquivalentBackgroundColor(Color);
+                    perceivedColor = GetPerceptiveBackgroundColor(Color);
                 }
 
                 if (ColorHelper.GetRelativeLuminance(perceivedColor) <= 0.5)
@@ -108,7 +107,7 @@ namespace Avalonia.Controls.Primitives
             {
                 // As a fallback, attempt to calculate using the overall control size
                 // This shouldn't happen as a track is a required template part of a slider
-                // However, if it does, the spectrum will still be shown
+                // However, if it does, the spectrum gradient will still be shown
                 pixelWidth = Convert.ToInt32(Bounds.Width * scale);
                 pixelHeight = Convert.ToInt32(Bounds.Height * scale);
             }
@@ -122,8 +121,8 @@ namespace Avalonia.Controls.Primitives
                     ColorModel,
                     ColorComponent,
                     HsvColor,
-                    IsAlphaMaxForced,
-                    IsSaturationValueMaxForced);
+                    IsAlphaVisible,
+                    IsPerceptive);
 
                 if (_backgroundBitmap != null)
                 {
@@ -316,40 +315,35 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         /// <param name="hsvColor">The actual color to get the equivalent background color for.</param>
         /// <returns>The equivalent, perceived background color.</returns>
-        private HsvColor GetEquivalentBackgroundColor(HsvColor hsvColor)
+        private HsvColor GetPerceptiveBackgroundColor(HsvColor hsvColor)
         {
             var component = ColorComponent;
-            var isAlphaMaxForced = IsAlphaMaxForced;
-            var isSaturationValueMaxForced = IsSaturationValueMaxForced;
+            var isAlphaVisible = IsAlphaVisible;
+            var isPerceptive = IsPerceptive;
 
-            if (isAlphaMaxForced &&
+            if (isAlphaVisible == false &&
                 component != ColorComponent.Alpha)
             {
                 hsvColor = new HsvColor(1.0, hsvColor.H, hsvColor.S, hsvColor.V);
             }
 
-            switch (component)
+            if (isPerceptive)
             {
-                case ColorComponent.Component1:
-                    return new HsvColor(
-                        hsvColor.A,
-                        hsvColor.H,
-                        isSaturationValueMaxForced ? 1.0 : hsvColor.S,
-                        isSaturationValueMaxForced ? 1.0 : hsvColor.V);
-                case ColorComponent.Component2:
-                    return new HsvColor(
-                        hsvColor.A,
-                        hsvColor.H,
-                        hsvColor.S,
-                        isSaturationValueMaxForced ? 1.0 : hsvColor.V);
-                case ColorComponent.Component3:
-                    return new HsvColor(
-                        hsvColor.A,
-                        hsvColor.H,
-                        isSaturationValueMaxForced ? 1.0 : hsvColor.S,
-                        hsvColor.V);
-                default:
-                    return hsvColor;
+                switch (component)
+                {
+                    case ColorComponent.Component1:
+                        return new HsvColor(hsvColor.A, hsvColor.H, 1.0, 1.0);
+                    case ColorComponent.Component2:
+                        return new HsvColor(hsvColor.A, hsvColor.H, hsvColor.S, 1.0);
+                    case ColorComponent.Component3:
+                        return new HsvColor(hsvColor.A, hsvColor.H, 1.0, hsvColor.V);
+                    default:
+                        return hsvColor;
+                }
+            }
+            else
+            {
+                return hsvColor;
             }
         }
 
@@ -359,18 +353,36 @@ namespace Avalonia.Controls.Primitives
         /// </summary>
         /// <param name="rgbColor">The actual color to get the equivalent background color for.</param>
         /// <returns>The equivalent, perceived background color.</returns>
-        private Color GetEquivalentBackgroundColor(Color rgbColor)
+        private Color GetPerceptiveBackgroundColor(Color rgbColor)
         {
             var component = ColorComponent;
-            var isAlphaMaxForced = IsAlphaMaxForced;
+            var isAlphaVisible = IsAlphaVisible;
+            var isPerceptive = IsPerceptive;
 
-            if (isAlphaMaxForced &&
+            if (isAlphaVisible == false &&
                 component != ColorComponent.Alpha)
             {
                 rgbColor = new Color(255, rgbColor.R, rgbColor.G, rgbColor.B);
             }
 
-            return rgbColor;
+            if (isPerceptive)
+            {
+                switch (component)
+                {
+                    case ColorComponent.Component1:
+                        return new Color(rgbColor.A, rgbColor.R, 0, 0);
+                    case ColorComponent.Component2:
+                        return new Color(rgbColor.A, 0, rgbColor.G, 0);
+                    case ColorComponent.Component3:
+                        return new Color(rgbColor.A, 0, 0, rgbColor.B);
+                    default:
+                        return rgbColor;
+                }
+            }
+            else
+            {
+                return rgbColor;
+            }
         }
 
         /// <inheritdoc/>
@@ -401,8 +413,8 @@ namespace Avalonia.Controls.Primitives
             }
             else if (change.Property == ColorComponentProperty ||
                      change.Property == ColorModelProperty ||
-                     change.Property == IsAlphaMaxForcedProperty ||
-                     change.Property == IsSaturationValueMaxForcedProperty)
+                     change.Property == IsAlphaVisibleProperty ||
+                     change.Property == IsPerceptiveProperty)
             {
                 ignorePropertyChanged = true;
 

src/Avalonia.Controls.ColorPicker/ColorSpectrum/ColorSpectrum.cs

@@ -45,6 +45,7 @@ namespace Avalonia.Controls.Primitives
 
         private bool _updatingColor = false;
         private bool _updatingHsvColor = false;
+        private bool _coercedInitialColor = false;
         private bool _isPointerPressed = false;
         private bool _shouldShowLargeSelection = false;
         private List<Hsv> _hsvValues = new List<Hsv>();
@@ -601,14 +602,102 @@ namespace Avalonia.Controls.Primitives
             }
         }
 
+        /// <summary>
+        /// Changes the currently selected color (always in HSV) and applies all necessary updates.
+        /// </summary>
+        /// <remarks>
+        /// Some additional logic is applied in certain situations to coerce and sync color values.
+        /// Use this method instead of update the <see cref="Color"/> or <see cref="HsvColor"/> directly.
+        /// </remarks>
+        /// <param name="newHsv">The new HSV color to change to.</param>
         private void UpdateColor(Hsv newHsv)
         {
             _updatingColor = true;
             _updatingHsvColor = true;
 
-            Rgb newRgb = newHsv.ToRgb();
             double alpha = HsvColor.A;
 
+            // It is common for the ColorPicker (and therefore the Spectrum) to be initialized
+            // with a #00000000 color value in some use cases. This is usually used to indicate
+            // that no color has been selected by the user. Note that #00000000 is different than
+            // #00FFFFFF (Transparent).
+            //
+            // In this situation, the first time the user clicks on the spectrum the third
+            // component and alpha component will remain zero. This is because the spectrum only
+            // controls two components at any given time.
+            //
+            // This is very unintuitive from a user-standpoint as after the user clicks on the
+            // spectrum they must then increase the alpha and then the third component sliders
+            // to the desired value. In fact, until they increase these slider values no color
+            // will show at all since it is fully transparent and black. In almost all cases
+            // though the desired value is simply full color.
+            //
+            // To work around this usability issue with an initial #00000000 color, the selected
+            // color is coerced (only the first time) into a color with maximum third component
+            // value and maximum alpha. This can only happen once and only if those two components
+            // are already zero.
+            //
+            // Also note this is NOT currently done for #00FFFFFF (Transparent) but based on
+            // further usability study that case may need to be handled here as well. Right now
+            // Transparent is treated as a normal color value with the alpha intentionally set
+            // to zero so the alpha slider must still be adjusted after the spectrum.
+            if (!_coercedInitialColor &&
+                IsLoaded)
+            {
+                bool isAlphaComponentZero = (alpha == 0.0);
+                bool isThirdComponentZero = false;
+
+                switch (Components)
+                {
+                    case ColorSpectrumComponents.HueValue:
+                    case ColorSpectrumComponents.ValueHue:
+                        isThirdComponentZero = (newHsv.S == 0.0);
+                        break;
+
+                    case ColorSpectrumComponents.HueSaturation:
+                    case ColorSpectrumComponents.SaturationHue:
+                        isThirdComponentZero = (newHsv.V == 0.0);
+                        break;
+
+                    case ColorSpectrumComponents.ValueSaturation:
+                    case ColorSpectrumComponents.SaturationValue:
+                        isThirdComponentZero = (newHsv.H == 0.0);
+                        break;
+                }
+
+                if (isAlphaComponentZero && isThirdComponentZero)
+                {
+                    alpha = 1.0;
+
+                    switch (Components)
+                    {
+                        case ColorSpectrumComponents.HueValue:
+                        case ColorSpectrumComponents.ValueHue:
+                            newHsv.S = 1.0;
+                            break;
+
+                        case ColorSpectrumComponents.HueSaturation:
+                        case ColorSpectrumComponents.SaturationHue:
+                            newHsv.V = 1.0;
+                            break;
+
+                        case ColorSpectrumComponents.ValueSaturation:
+                        case ColorSpectrumComponents.SaturationValue:
+                            // Hue is mathematically NOT a special case; however, is one conceptually.
+                            // It doesn't make sense to change the selected Hue value, so why is it set here?
+                            // Setting to 360.0 is equivalent to the max set for other components and is
+                            // internally wrapped back to 0.0 (since 360 degrees = 0 degrees).
+                            // This means effectively there is no change to the hue component value.
+                            newHsv.H = 360.0;
+                            break;
+                    }
+
+                    _coercedInitialColor = true;
+                }
+            }
+
+            Rgb newRgb = newHsv.ToRgb();
+
             SetCurrentValue(ColorProperty, newRgb.ToColor(alpha));
             SetCurrentValue(HsvColorProperty, newHsv.ToHsvColor(alpha));
 

src/Avalonia.Controls.ColorPicker/ColorView/ColorView.Properties.cs

@@ -504,6 +504,12 @@ namespace Avalonia.Controls
         /// <summary>
         /// Gets or sets the index of the selected tab/panel/page (subview).
         /// </summary>
+        /// <remarks>
+        /// When using the default control theme, this property is designed to be used with the
+        /// <see cref="ColorViewTab"/> enum. The <see cref="ColorViewTab"/> enum defines the
+        /// index values of each of the three standard tabs.
+        /// Use like `SelectedIndex = (int)ColorViewTab.Palette`.
+        /// </remarks>
         public int SelectedIndex
         {
             get => GetValue(SelectedIndexProperty);

src/Avalonia.Controls.ColorPicker/Helpers/ColorPickerHelpers.cs

@@ -29,11 +29,10 @@ namespace Avalonia.Controls.Primitives
         /// <param name="colorModel">The color model being used: RGBA or HSVA.</param>
         /// <param name="component">The specific color component to sweep.</param>
         /// <param name="baseHsvColor">The base HSV color used for components not being changed.</param>
-        /// <param name="isAlphaMaxForced">Fix the alpha component value to maximum during calculation.
-        /// This will remove any alpha/transparency from the other component backgrounds.</param>
-        /// <param name="isSaturationValueMaxForced">Fix the saturation and value components to maximum
-        /// during calculation with the HSVA color model.
-        /// This will ensure colors are always discernible regardless of saturation/value.</param>
+        /// <param name="isAlphaVisible">Whether the alpha component is visible and rendered in the bitmap.
+        /// This property is ignored when the alpha component itself is being rendered.</param>
+        /// <param name="isPerceptive">Whether the slider adapts rendering to improve user-perception over exactness.
+        /// This will ensure colors are always discernible.</param>
         /// <returns>A new bitmap representing a gradient of color component values.</returns>
         public static async Task<ArrayList<byte>> CreateComponentBitmapAsync(
             int width,
@@ -42,8 +41,8 @@ namespace Avalonia.Controls.Primitives
             ColorModel colorModel,
             ColorComponent component,
             HsvColor baseHsvColor,
-            bool isAlphaMaxForced,
-            bool isSaturationValueMaxForced)
+            bool isAlphaVisible,
+            bool isPerceptive)
         {
             if (width == 0 || height == 0)
             {
@@ -67,7 +66,7 @@ namespace Avalonia.Controls.Primitives
                 bgraPixelDataWidth  = width * 4;
 
                 // Maximize alpha component value
-                if (isAlphaMaxForced &&
+                if (isAlphaVisible == false &&
                     component != ColorComponent.Alpha)
                 {
                     baseHsvColor = new HsvColor(1.0, baseHsvColor.H, baseHsvColor.S, baseHsvColor.V);
@@ -79,22 +78,41 @@ namespace Avalonia.Controls.Primitives
                     baseRgbColor = baseHsvColor.ToRgb();
                 }
 
-                // Maximize Saturation and Value components when in HSVA mode
-                if (isSaturationValueMaxForced &&
-                    colorModel == ColorModel.Hsva &&
+                // Apply any perceptive adjustments to the color
+                if (isPerceptive &&
                     component != ColorComponent.Alpha)
                 {
-                    switch (component)
+                    if (colorModel == ColorModel.Hsva)
                     {
-                        case ColorComponent.Component1:
-                            baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, 1.0, 1.0);
-                            break;
-                        case ColorComponent.Component2:
-                            baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, baseHsvColor.S, 1.0);
-                            break;
-                        case ColorComponent.Component3:
-                            baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, 1.0, baseHsvColor.V);
-                            break;
+                        // Maximize Saturation and Value components
+                        switch (component)
+                        {
+                            case ColorComponent.Component1: // Hue
+                                baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, 1.0, 1.0);
+                                break;
+                            case ColorComponent.Component2: // Saturation
+                                baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, baseHsvColor.S, 1.0);
+                                break;
+                            case ColorComponent.Component3: // Value
+                                baseHsvColor = new HsvColor(baseHsvColor.A, baseHsvColor.H, 1.0, baseHsvColor.V);
+                                break;
+                        }
+                    }
+                    else
+                    {
+                        // Minimize component values other than the current one
+                        switch (component)
+                        {
+                            case ColorComponent.Component1: // Red
+                                baseRgbColor = new Color(baseRgbColor.A, baseRgbColor.R, 0, 0);
+                                break;
+                            case ColorComponent.Component2: // Green
+                                baseRgbColor = new Color(baseRgbColor.A, 0, baseRgbColor.G, 0);
+                                break;
+                            case ColorComponent.Component3: // Blue
+                                baseRgbColor = new Color(baseRgbColor.A, 0, 0, baseRgbColor.B);
+                                break;
+                        }
                     }
                 }
 

src/Avalonia.Controls.ColorPicker/Helpers/Hsv.cs

@@ -11,7 +11,7 @@ namespace Avalonia.Controls.Primitives
     /// Contains and allows modification of Hue, Saturation and Value components.
     /// </summary>
     /// <remarks>
-    ///   The is a specialized struct optimized for permanence and memory:
+    ///   The is a specialized struct optimized for performance and memory:
     ///   <list type="bullet">
     ///     <item>This is not a read-only struct like <see cref="HsvColor"/> and allows editing the fields</item>
     ///     <item>Removes the alpha component unnecessary in core calculations</item>

src/Avalonia.Controls.ColorPicker/Helpers/Rgb.cs

@@ -12,7 +12,7 @@ namespace Avalonia.Controls.Primitives
     /// Contains and allows modification of Red, Green and Blue components.
     /// </summary>
     /// <remarks>
-    ///   The is a specialized struct optimized for permanence and memory:
+    ///   The is a specialized struct optimized for performance and memory:
     ///   <list type="bullet">
     ///     <item>This is not a read-only struct like <see cref="Color"/> and allows editing the fields</item>
     ///     <item>Removes the alpha component unnecessary in core calculations</item>

src/Avalonia.Controls.ColorPicker/Themes/Fluent/ColorPicker.xaml

@@ -113,8 +113,8 @@
                       <primitives:ColorSlider x:Name="ColorSpectrumThirdComponentSlider"
                                               AutomationProperties.Name="Third Component"
                                               Grid.Column="0"
-                                              IsAlphaMaxForced="True"
-                                              IsSaturationValueMaxForced="False"
+                                              IsAlphaVisible="False"
+                                              IsPerceptive="True"
                                               Orientation="Vertical"
                                               ColorModel="Hsva"
                                               ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"
@@ -490,11 +490,11 @@
                   </TabItem>
                 </TabControl>
                 <!-- Previewer -->
-                <!-- Note that top/bottom margins have -5 to remove for drop shadow padding -->
+                <!-- Note that the drop shadow is allowed to extend past the control bounds -->
                 <primitives:ColorPreviewer Grid.Row="1"
                                            HsvColor="{Binding HsvColor, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                            IsAccentColorsVisible="{TemplateBinding IsAccentColorsVisible}"
-                                           Margin="12,-5,12,7"
+                                           Margin="12,0,12,12"
                                            IsVisible="{TemplateBinding IsColorPreviewVisible}" />
               </Grid>
             </Flyout>
@@ -502,6 +502,23 @@
         </DropDownButton>
       </ControlTemplate>
     </Setter>
+
+    <!--
+    <Style Selector="^ /template/ primitives|ColorSlider#ColorSpectrumThirdComponentSlider[ColorComponent=Component1]">
+      <Setter Property="IsPerceptive" Value="True" />
+    </Style>
+
+    <Style Selector="^ /template/ primitives|ColorSlider#Component1Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component2Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component3Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    -->
+
   </ControlTheme>
 
 </ResourceDictionary>

src/Avalonia.Controls.ColorPicker/Themes/Fluent/ColorPreviewer.xaml

@@ -8,7 +8,9 @@
 
   <ControlTheme x:Key="{x:Type ColorPreviewer}"
                 TargetType="ColorPreviewer">
-    <Setter Property="Height" Value="70" />
+    <Setter Property="Height" Value="50" />
+    <!-- The preview color drop shadow is allowed to extend outside the control bounds -->
+    <Setter Property="ClipToBounds" Value="False" />
     <Setter Property="CornerRadius" Value="{DynamicResource ControlCornerRadius}" />
     <Setter Property="Template">
       <ControlTemplate TargetType="{x:Type ColorPreviewer}">
@@ -21,7 +23,6 @@
                   Height="{StaticResource ColorPreviewerAccentSectionHeight}"
                   Width="{StaticResource ColorPreviewerAccentSectionWidth}"
                   ColumnDefinitions="*,*"
-                  Margin="0,0,-10,0"
                   VerticalAlignment="Center">
               <Border Grid.Column="0"
                       Grid.ColumnSpan="2"
@@ -43,7 +44,6 @@
                   Height="{StaticResource ColorPreviewerAccentSectionHeight}"
                   Width="{StaticResource ColorPreviewerAccentSectionWidth}"
                   ColumnDefinitions="*,*"
-                  Margin="-10,0,0,0"
                   VerticalAlignment="Center">
               <Border Grid.Column="0"
                       Grid.ColumnSpan="2"
@@ -64,10 +64,8 @@
             <Border Grid.Column="1"
                     HorizontalAlignment="Stretch"
                     VerticalAlignment="Stretch"
-                    Background="Transparent"
                     BoxShadow="0 0 10 2 #BF000000"
-                    CornerRadius="{TemplateBinding CornerRadius}"
-                    Margin="10">
+                    CornerRadius="{TemplateBinding CornerRadius}">
               <Panel>
                 <Border Background="{StaticResource ColorControlCheckeredBackgroundBrush}"
                         CornerRadius="{TemplateBinding CornerRadius}" />
@@ -82,8 +80,7 @@
           <Border CornerRadius="{TemplateBinding CornerRadius}"
                   IsVisible="{TemplateBinding IsAccentColorsVisible, Converter={x:Static BoolConverters.Not}}"
                   HorizontalAlignment="Stretch"
-                  VerticalAlignment="Stretch"
-                  Margin="0,10,0,10">
+                  VerticalAlignment="Stretch">
             <Panel>
               <Border Background="{StaticResource ColorControlCheckeredBackgroundBrush}"
                       CornerRadius="{TemplateBinding CornerRadius}" />

src/Avalonia.Controls.ColorPicker/Themes/Fluent/ColorView.xaml

@@ -360,8 +360,8 @@
                 <primitives:ColorSlider x:Name="ColorSpectrumThirdComponentSlider"
                                         AutomationProperties.Name="Third Component"
                                         Grid.Column="0"
-                                        IsAlphaMaxForced="True"
-                                        IsSaturationValueMaxForced="False"
+                                        IsAlphaVisible="False"
+                                        IsPerceptive="True"
                                         Orientation="Vertical"
                                         ColorModel="Hsva"
                                         ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"
@@ -737,15 +737,32 @@
             </TabItem>
           </TabControl>
           <!-- Previewer -->
-          <!-- Note that top/bottom margins have -5 to remove for drop shadow padding -->
+          <!-- Note that the drop shadow is allowed to extend past the control bounds -->
           <primitives:ColorPreviewer Grid.Row="1"
                                      HsvColor="{Binding HsvColor, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                      IsAccentColorsVisible="{TemplateBinding IsAccentColorsVisible}"
-                                     Margin="12,-5,12,7"
+                                     Margin="12,0,12,12"
                                      IsVisible="{TemplateBinding IsColorPreviewVisible}" />
         </Grid>
       </ControlTemplate>
     </Setter>
+
+    <!--
+    <Style Selector="^ /template/ primitives|ColorSlider#ColorSpectrumThirdComponentSlider[ColorComponent=Component1]">
+      <Setter Property="IsPerceptive" Value="True" />
+    </Style>
+
+    <Style Selector="^ /template/ primitives|ColorSlider#Component1Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component2Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component3Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    -->
+
   </ControlTheme>
 
 </ResourceDictionary>

src/Avalonia.Controls.ColorPicker/Themes/Simple/ColorPicker.xaml

@@ -112,8 +112,8 @@
                       <primitives:ColorSlider x:Name="ColorSpectrumThirdComponentSlider"
                                               AutomationProperties.Name="Third Component"
                                               Grid.Column="0"
-                                              IsAlphaMaxForced="True"
-                                              IsSaturationValueMaxForced="False"
+                                              IsAlphaVisible="False"
+                                              IsPerceptive="True"
                                               Orientation="Vertical"
                                               ColorModel="Hsva"
                                               ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"
@@ -489,11 +489,11 @@
                   </TabItem>
                 </TabControl>
                 <!-- Previewer -->
-                <!-- Note that top/bottom margins have -5 to remove for drop shadow padding -->
+                <!-- Note that the drop shadow is allowed to extend past the control bounds -->
                 <primitives:ColorPreviewer Grid.Row="1"
                                            HsvColor="{Binding HsvColor, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                            IsAccentColorsVisible="{TemplateBinding IsAccentColorsVisible}"
-                                           Margin="12,-5,12,7"
+                                           Margin="12,0,12,12"
                                            IsVisible="{TemplateBinding IsColorPreviewVisible}" />
               </Grid>
             </Flyout>
@@ -501,6 +501,23 @@
         </DropDownButton>
       </ControlTemplate>
     </Setter>
+
+    <!--
+    <Style Selector="^ /template/ primitives|ColorSlider#ColorSpectrumThirdComponentSlider[ColorComponent=Component1]">
+      <Setter Property="IsPerceptive" Value="True" />
+    </Style>
+
+    <Style Selector="^ /template/ primitives|ColorSlider#Component1Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component2Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component3Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    -->
+
   </ControlTheme>
 
 </ResourceDictionary>

src/Avalonia.Controls.ColorPicker/Themes/Simple/ColorPreviewer.xaml

@@ -8,7 +8,9 @@
 
   <ControlTheme x:Key="{x:Type ColorPreviewer}"
                 TargetType="ColorPreviewer">
-    <Setter Property="Height" Value="70" />
+    <Setter Property="Height" Value="50" />
+    <!-- The preview color drop shadow is allowed to extend outside the control bounds -->
+    <Setter Property="ClipToBounds" Value="False" />
     <Setter Property="CornerRadius" Value="0" />
     <Setter Property="Template">
       <ControlTemplate TargetType="{x:Type ColorPreviewer}">
@@ -21,7 +23,6 @@
                   Height="{StaticResource ColorPreviewerAccentSectionHeight}"
                   Width="{StaticResource ColorPreviewerAccentSectionWidth}"
                   ColumnDefinitions="*,*"
-                  Margin="0,0,-10,0"
                   VerticalAlignment="Center">
               <Border Grid.Column="0"
                       Grid.ColumnSpan="2"
@@ -43,7 +44,6 @@
                   Height="{StaticResource ColorPreviewerAccentSectionHeight}"
                   Width="{StaticResource ColorPreviewerAccentSectionWidth}"
                   ColumnDefinitions="*,*"
-                  Margin="-10,0,0,0"
                   VerticalAlignment="Center">
               <Border Grid.Column="0"
                       Grid.ColumnSpan="2"
@@ -64,10 +64,8 @@
             <Border Grid.Column="1"
                     HorizontalAlignment="Stretch"
                     VerticalAlignment="Stretch"
-                    Background="Transparent"
                     BoxShadow="0 0 10 2 #BF000000"
-                    CornerRadius="{TemplateBinding CornerRadius}"
-                    Margin="10">
+                    CornerRadius="{TemplateBinding CornerRadius}">
               <Panel>
                 <Border Background="{StaticResource ColorControlCheckeredBackgroundBrush}"
                         CornerRadius="{TemplateBinding CornerRadius}" />
@@ -82,8 +80,7 @@
           <Border CornerRadius="{TemplateBinding CornerRadius}"
                   IsVisible="{TemplateBinding IsAccentColorsVisible, Converter={x:Static BoolConverters.Not}}"
                   HorizontalAlignment="Stretch"
-                  VerticalAlignment="Stretch"
-                  Margin="0,10,0,10">
+                  VerticalAlignment="Stretch">
             <Panel>
               <Border Background="{StaticResource ColorControlCheckeredBackgroundBrush}"
                       CornerRadius="{TemplateBinding CornerRadius}" />

src/Avalonia.Controls.ColorPicker/Themes/Simple/ColorView.xaml

@@ -322,8 +322,8 @@
                 <primitives:ColorSlider x:Name="ColorSpectrumThirdComponentSlider"
                                         AutomationProperties.Name="Third Component"
                                         Grid.Column="0"
-                                        IsAlphaMaxForced="True"
-                                        IsSaturationValueMaxForced="False"
+                                        IsAlphaVisible="False"
+                                        IsPerceptive="True"
                                         Orientation="Vertical"
                                         ColorModel="Hsva"
                                         ColorComponent="{Binding ThirdComponent, ElementName=ColorSpectrum}"
@@ -699,15 +699,32 @@
             </TabItem>
           </TabControl>
           <!-- Previewer -->
-          <!-- Note that top/bottom margins have -5 to remove for drop shadow padding -->
+          <!-- Note that the drop shadow is allowed to extend past the control bounds -->
           <primitives:ColorPreviewer Grid.Row="1"
                                      HsvColor="{Binding HsvColor, RelativeSource={RelativeSource TemplatedParent}, Mode=TwoWay}"
                                      IsAccentColorsVisible="{TemplateBinding IsAccentColorsVisible}"
-                                     Margin="12,-5,12,7"
+                                     Margin="12,0,12,12"
                                      IsVisible="{TemplateBinding IsColorPreviewVisible}" />
         </Grid>
       </ControlTemplate>
     </Setter>
+
+    <!--
+    <Style Selector="^ /template/ primitives|ColorSlider#ColorSpectrumThirdComponentSlider[ColorComponent=Component1]">
+      <Setter Property="IsPerceptive" Value="True" />
+    </Style>
+
+    <Style Selector="^ /template/ primitives|ColorSlider#Component1Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component2Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    <Style Selector="^ /template/ primitives|ColorSlider#Component3Slider[ColorModel=Rgba]">
+      <Setter Property="IsPerceptive" Value="False" />
+    </Style>
+    -->
+
   </ControlTheme>
 
 </ResourceDictionary>

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -3958,7 +3958,7 @@ namespace Avalonia.Controls
             {
                 bool focusLeftDataGrid = true;
                 bool dataGridWillReceiveRoutedEvent = true;
-                Visual focusedObject = FocusManager.Instance.Current as Visual;
+                Visual focusedObject = FocusManager.GetFocusManager(this)?.GetFocusedElement() as Visual;
                 DataGridColumn editingColumn = null;
 
                 while (focusedObject != null)
@@ -4865,7 +4865,8 @@ namespace Avalonia.Controls
             if (!ctrl)
             {
                 // If Enter was used by a TextBox, we shouldn't handle the key
-                if (FocusManager.Instance.Current is TextBox focusedTextBox && focusedTextBox.AcceptsReturn)
+                if (FocusManager.GetFocusManager(this)?.GetFocusedElement() is TextBox focusedTextBox
+                    && focusedTextBox.AcceptsReturn)
                 {
                     return false;
                 }

src/Avalonia.Controls.ItemsRepeater/Controls/ViewManager.cs

@@ -695,7 +695,7 @@ namespace Avalonia.Controls
         {
             Control? focusedElement = null;
 
-            if (FocusManager.Instance?.Current is Visual child)
+            if (TopLevel.GetTopLevel(_owner)?.FocusManager?.GetFocusedElement() is Visual child)
             {
                 var parent = child.GetVisualParent();
                 var owner = _owner;

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.cs

@@ -762,7 +762,7 @@ namespace Avalonia.Controls
         /// otherwise, false.</returns>
         protected bool HasFocus()
         {
-            Visual? focused = FocusManager.Instance?.Current as Visual;
+            Visual? focused = FocusManager.GetFocusManager(this)?.GetFocusedElement() as Visual;
 
             while (focused != null)
             {

src/Avalonia.Controls/Calendar/Calendar.cs

@@ -1567,7 +1567,7 @@ namespace Avalonia.Controls
             base.OnPointerReleased(e);
             if (!HasFocusInternal && e.InitialPressMouseButton == MouseButton.Left)
             {
-                FocusManager.Instance?.Focus(this);
+                Focus();
             }
         }
 

src/Avalonia.Controls/Calendar/CalendarItem.cs

@@ -171,7 +171,7 @@ namespace Avalonia.Controls.Primitives
                 var childCount = Calendar.RowsPerMonth + Calendar.RowsPerMonth * Calendar.ColumnsPerMonth;
                 using var children = new PooledList<Control>(childCount);
 
-                for (int i = 0; i < Calendar.RowsPerMonth; i++)
+                for (int i = 0; i < Calendar.ColumnsPerMonth; i++)
                 {
                     if (DayTitleTemplate?.Build() is Control cell)
                     {

src/Avalonia.Controls/ComboBox.cs

@@ -230,8 +230,7 @@ namespace Avalonia.Controls
                 var firstChild = Presenter?.Panel?.Children.FirstOrDefault(c => CanFocus(c));
                 if (firstChild != null)
                 {
-                    FocusManager.Instance?.Focus(firstChild, NavigationMethod.Directional);
-                    e.Handled = true;
+                    e.Handled = firstChild.Focus(NavigationMethod.Directional);
                 }
             }
         }

src/Avalonia.Controls/ContextMenu.cs

@@ -285,7 +285,7 @@ namespace Avalonia.Controls
             }
         }
 
-        void ISetterValue.Initialize(ISetter setter)
+        void ISetterValue.Initialize(SetterBase setter)
         {
             // ContextMenu can be assigned to the ContextMenu property in a setter. This overrides
             // the behavior defined in Control which requires controls to be wrapped in a <template>.
@@ -360,7 +360,7 @@ namespace Avalonia.Controls
 
         private void PopupOpened(object? sender, EventArgs e)
         {
-            _previousFocus = FocusManager.Instance?.Current;
+            _previousFocus = FocusManager.GetFocusManager(this)?.GetFocusedElement();
             Focus();
 
             _popupHostChangedHandler?.Invoke(_popup!.Host);
@@ -390,7 +390,7 @@ namespace Avalonia.Controls
             }
 
             // HACK: Reset the focus when the popup is closed. We need to fix this so it's automatic.
-            FocusManager.Instance?.Focus(_previousFocus);
+            _previousFocus?.Focus();
 
             RaiseEvent(new RoutedEventArgs
             {

src/Avalonia.Controls/Control.cs

@@ -213,7 +213,7 @@ namespace Avalonia.Controls
         bool IDataTemplateHost.IsDataTemplatesInitialized => _dataTemplates != null;
 
         /// <inheritdoc/>
-        void ISetterValue.Initialize(ISetter setter)
+        void ISetterValue.Initialize(SetterBase setter)
         {
             if (setter is Setter s && s.Property == ContextFlyoutProperty)
             {

src/Avalonia.Controls/DateTimePickers/DatePickerPresenter.cs

@@ -323,10 +323,11 @@ namespace Avalonia.Controls
                     e.Handled = true;
                     break;
                 case Key.Tab:
-                    if (FocusManager.Instance?.Current is IInputElement focus)
+                    var focusManager = FocusManager.GetFocusManager(this);
+                    if (focusManager?.GetFocusedElement() is { } focus)
                     {
                         var nextFocus = KeyboardNavigationHandler.GetNext(focus, NavigationDirection.Next);
-                        KeyboardDevice.Instance?.SetFocusedElement(nextFocus, NavigationMethod.Tab, KeyModifiers.None);
+                        nextFocus?.Focus(NavigationMethod.Tab);
                         e.Handled = true;
                     }
                     break;
@@ -449,15 +450,15 @@ namespace Avalonia.Controls
 
             if (monthCol < dayCol && monthCol < yearCol)
             {
-                KeyboardDevice.Instance?.SetFocusedElement(_monthSelector, NavigationMethod.Pointer, KeyModifiers.None);
+                _monthSelector?.Focus(NavigationMethod.Pointer);
             }
             else if (dayCol < monthCol && dayCol < yearCol)
             {
-                KeyboardDevice.Instance?.SetFocusedElement(_daySelector, NavigationMethod.Pointer, KeyModifiers.None);
+                _monthSelector?.Focus(NavigationMethod.Pointer);
             }
             else if (yearCol < monthCol && yearCol < dayCol)
             {
-                KeyboardDevice.Instance?.SetFocusedElement(_yearSelector, NavigationMethod.Pointer, KeyModifiers.None);
+                _yearSelector?.Focus(NavigationMethod.Pointer);
             }
         }
 

src/Avalonia.Controls/DateTimePickers/TimePickerPresenter.cs

@@ -161,10 +161,10 @@ namespace Avalonia.Controls
                     e.Handled = true;
                     break;
                 case Key.Tab:
-                    if (FocusManager.Instance?.Current is IInputElement focus)
+                    if (FocusManager.GetFocusManager(this)?.GetFocusedElement() is { } focus)
                     {
                         var nextFocus = KeyboardNavigationHandler.GetNext(focus, NavigationDirection.Next);
-                        KeyboardDevice.Instance?.SetFocusedElement(nextFocus, NavigationMethod.Tab, KeyModifiers.None);
+                        nextFocus?.Focus(NavigationMethod.Tab);
                         e.Handled = true;
                     }
                     break;
@@ -216,7 +216,7 @@ namespace Avalonia.Controls
             _periodSelector.SelectedValue = hr >= 12 ? 1 : 0;
 
             SetGrid();
-            KeyboardDevice.Instance?.SetFocusedElement(_hourSelector, NavigationMethod.Pointer, KeyModifiers.None);
+            _hourSelector?.Focus(NavigationMethod.Pointer);
         }
 
         private void SetGrid()

src/Avalonia.Controls/Flyouts/PopupFlyoutBase.cs

@@ -250,14 +250,14 @@ namespace Avalonia.Controls.Primitives
                 // Try and focus content inside Flyout
                 if (Popup.Child.Focusable)
                 {
-                    FocusManager.Instance?.Focus(Popup.Child);
+                    Popup.Child.Focus();
                 }
                 else
                 {
                     var nextFocus = KeyboardNavigationHandler.GetNext(Popup.Child, NavigationDirection.Next);
                     if (nextFocus != null)
                     {
-                        FocusManager.Instance?.Focus(nextFocus);
+                        nextFocus.Focus();
                     }
                 }
             }

src/Avalonia.Controls/ItemsControl.cs

@@ -566,19 +566,20 @@ namespace Avalonia.Controls
         {
             if (!e.Handled)
             {
-                var focus = FocusManager.Instance;
+                var focus = FocusManager.GetFocusManager(this);
                 var direction = e.Key.ToNavigationDirection();
                 var container = Presenter?.Panel as INavigableContainer;
 
-                if (container == null ||
-                    focus?.Current == null ||
+                if (focus == null ||
+                    container == null ||
+                    focus.GetFocusedElement() == null ||
                     direction == null ||
                     direction.Value.IsTab())
                 {
                     return;
                 }
 
-                Visual? current = focus.Current as Visual;
+                Visual? current = focus.GetFocusedElement() as Visual;
 
                 while (current != null)
                 {
@@ -588,7 +589,7 @@ namespace Avalonia.Controls
 
                         if (next != null)
                         {
-                            focus.Focus(next, NavigationMethod.Directional, e.KeyModifiers);
+                            next.Focus(NavigationMethod.Directional, e.KeyModifiers);
                             e.Handled = true;
                         }
 

src/Avalonia.Controls/Primitives/Popup.cs

@@ -727,7 +727,7 @@ namespace Avalonia.Controls.Primitives
 
             Closed?.Invoke(this, EventArgs.Empty);
 
-            var focusCheck = FocusManager.Instance?.Current;
+            var focusCheck = FocusManager.GetFocusManager(this)?.GetFocusedElement();
 
             // Focus is set to null as part of popup closing, so we only want to
             // set focus to PlacementTarget if this is the case
@@ -744,7 +744,7 @@ namespace Avalonia.Controls.Primitives
 
                     if (e is object)
                     {
-                        FocusManager.Instance?.Focus(e);
+                        e.Focus();
                     }
                 }
                 else
@@ -752,7 +752,7 @@ namespace Avalonia.Controls.Primitives
                     var anc = this.FindLogicalAncestorOfType<Control>();
                     if (anc != null)
                     {
-                        FocusManager.Instance?.Focus(anc);
+                        anc.Focus();
                     }
                 }
             }

src/Avalonia.Controls/TopLevel.cs

@@ -452,6 +452,9 @@ namespace Avalonia.Controls
         /// </summary>
         public IClipboard? Clipboard => PlatformImpl?.TryGetFeature<IClipboard>();
 
+        /// <inheritdoc />
+        public IFocusManager? FocusManager => AvaloniaLocator.Current.GetService<IFocusManager>();
+
         /// <inheritdoc/>
         Point IRenderRoot.PointToClient(PixelPoint p)
         {
@@ -725,7 +728,7 @@ namespace Avalonia.Controls
 
         void PlatformImpl_LostFocus()
         {
-            var focused = (Visual?)FocusManager.Instance?.Current;
+            var focused = (Visual?)FocusManager?.GetFocusedElement();
             if (focused == null)
                 return;
             while (focused.VisualParent != null)

src/Avalonia.Controls/TreeView.cs

@@ -560,8 +560,7 @@ namespace Avalonia.Controls
 
                     if (next != null)
                     {
-                        FocusManager.Instance?.Focus(next, NavigationMethod.Directional);
-                        e.Handled = true;
+                        e.Handled = next.Focus(NavigationMethod.Directional);
                     }
                 }
                 else

src/Avalonia.Controls/TreeViewItem.cs

@@ -238,7 +238,7 @@ namespace Avalonia.Controls
                         }
                         else
                         {
-                            FocusManager.Instance?.Focus(treeViewItem, NavigationMethod.Directional);
+                            treeViewItem.Focus(NavigationMethod.Directional);
                         }
 
                         return true;

src/Avalonia.Controls/VirtualizingStackPanel.cs

@@ -343,7 +343,7 @@ namespace Avalonia.Controls
         {
             var items = Items;
 
-            if (_isInLayout || index < 0 || index >= items.Count || _realizedElements is null)
+            if (_isInLayout || index < 0 || index >= items.Count || _realizedElements is null || !IsEffectivelyVisible)
                 return null;
 
             if (GetRealizedElement(index) is Control element)

src/Avalonia.Controls/WindowBase.cs

@@ -234,7 +234,7 @@ namespace Avalonia.Controls
 
                 if (this is IFocusScope scope)
                 {
-                    FocusManager.Instance?.RemoveFocusScope(scope);
+                    ((FocusManager?)FocusManager)?.RemoveFocusScope(scope);
                 }
 
                 base.HandleClosed();
@@ -326,7 +326,7 @@ namespace Avalonia.Controls
 
             if (scope != null)
             {
-                FocusManager.Instance?.SetFocusScope(scope);
+                ((FocusManager?)FocusManager)?.SetFocusScope(scope);
             }
 
             IsActive = true;

src/Avalonia.Diagnostics/Diagnostics/DevTools.cs

@@ -86,7 +86,7 @@ namespace Avalonia.Diagnostics
         private static IDisposable Open(IDevToolsTopLevelGroup topLevelGroup, DevToolsOptions options,
             Window? owner, Application? app)
         {
-            var focussedControl = KeyboardDevice.Instance?.FocusedElement as Control;
+            var focusedControl = owner?.FocusManager?.GetFocusedElement() as Control;
             AvaloniaObject root = topLevelGroup switch
             {
                 ClassicDesktopStyleApplicationLifetimeTopLevelGroup gr => new Controls.Application(gr, app ?? Application.Current!),
@@ -98,7 +98,7 @@ namespace Avalonia.Diagnostics
             if (s_open.TryGetValue(topLevelGroup, out var mainWindow))
             {
                 mainWindow.Activate();
-                mainWindow.SelectedControl(focussedControl);
+                mainWindow.SelectedControl(focusedControl);
                 return Disposable.Empty;
             }
             if (topLevelGroup.Items.Count == 1 && topLevelGroup.Items is not INotifyCollectionChanged)
@@ -110,7 +110,7 @@ namespace Avalonia.Diagnostics
                     if (group.Key.Items.Contains(singleTopLevel))
                     {
                         group.Value.Activate();
-                        group.Value.SelectedControl(focussedControl);
+                        group.Value.SelectedControl(focusedControl);
                         return Disposable.Empty;
                     }
                 }
@@ -124,7 +124,7 @@ namespace Avalonia.Diagnostics
                 Tag = topLevelGroup
             };
             window.SetOptions(options);
-            window.SelectedControl(focussedControl);
+            window.SelectedControl(focusedControl);
             window.Closed += DevToolsClosed;
             s_open.Add(topLevelGroup, window);
             if (options.ShowAsChildWindow && owner is not null)

src/Avalonia.Diagnostics/Diagnostics/ViewModels/ControlDetailsViewModel.cs

@@ -64,7 +64,7 @@ namespace Avalonia.Diagnostics.ViewModels
                 // We need to place styles without activator first, such styles will be overwritten by ones with activators.
                 foreach (var appliedStyle in styleDiagnostics.AppliedStyles.OrderBy(s => s.HasActivator))
                 {
-                    var styleSource = appliedStyle.Source;
+                    var styleSource = appliedStyle.Style;
 
                     var setters = new List<SetterViewModel>();
 

src/Avalonia.Diagnostics/Diagnostics/ViewModels/StyleViewModel.cs

@@ -5,11 +5,11 @@ namespace Avalonia.Diagnostics.ViewModels
 {
     internal class StyleViewModel : ViewModelBase
     {
-        private readonly IStyleInstance _styleInstance;
+        private readonly AppliedStyle _styleInstance;
         private bool _isActive;
         private bool _isVisible;
 
-        public StyleViewModel(IStyleInstance styleInstance, string name, List<SetterViewModel> setters)
+        public StyleViewModel(AppliedStyle styleInstance, string name, List<SetterViewModel> setters)
         {
             _styleInstance = styleInstance;
             IsVisible = true;

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs

@@ -107,7 +107,7 @@ namespace Avalonia.LinuxFramebuffer
 
                     if (_topLevel is IFocusScope scope)
                     {
-                        FocusManager.Instance?.SetFocusScope(scope);
+                        ((FocusManager)_topLevel.FocusManager).SetFocusScope(scope);
                     }
                 }
 

src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlBindingPathTransformer.cs

@@ -125,7 +125,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
                 var selfType = context.ParentNodes().OfType<XamlAstConstructableObjectNode>().First().Type.GetClrType();
                 
                 // When using self bindings with setters we need to change target type to resolved selector type.
-                if (context.GetAvaloniaTypes().ISetter.IsAssignableFrom(selfType))
+                if (context.GetAvaloniaTypes().SetterBase.IsAssignableFrom(selfType))
                 {
                     selfType = context.ParentNodes().OfType<AvaloniaXamlIlTargetTypeMetadataNode>().First().TargetType.GetClrType();
                 }

src/Markup/Avalonia.Markup.Xaml.Loader/CompilerExtensions/Transformers/AvaloniaXamlIlWellKnownTypes.cs

@@ -104,7 +104,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
         public IXamlType TextDecorationCollection { get; }
         public IXamlType TextDecorations { get; }
         public IXamlType TextTrimming { get; }
-        public IXamlType ISetter { get; }
+        public IXamlType SetterBase { get; }
         public IXamlType IStyle { get; }
         public IXamlType StyleInclude { get; }
         public IXamlType ResourceInclude { get; }
@@ -244,7 +244,7 @@ namespace Avalonia.Markup.Xaml.XamlIl.CompilerExtensions.Transformers
             TextDecorationCollection = cfg.TypeSystem.GetType("Avalonia.Media.TextDecorationCollection");
             TextDecorations = cfg.TypeSystem.GetType("Avalonia.Media.TextDecorations");
             TextTrimming = cfg.TypeSystem.GetType("Avalonia.Media.TextTrimming");
-            ISetter = cfg.TypeSystem.GetType("Avalonia.Styling.ISetter");
+            SetterBase = cfg.TypeSystem.GetType("Avalonia.Styling.SetterBase");
             IStyle = cfg.TypeSystem.GetType("Avalonia.Styling.IStyle");
             StyleInclude = cfg.TypeSystem.GetType("Avalonia.Markup.Xaml.Styling.StyleInclude");
             ResourceInclude = cfg.TypeSystem.GetType("Avalonia.Markup.Xaml.Styling.ResourceInclude");

src/Markup/Avalonia.Markup.Xaml/XamlIl/Runtime/XamlIlRuntimeHelpers.cs

@@ -154,7 +154,8 @@ namespace Avalonia.Markup.Xaml.XamlIl.Runtime
                 var namespaces = _nsInfo.XmlNamespaces;
                 if (!namespaces.TryGetValue(ns, out var lst))
                     throw new ArgumentException("Unable to resolve namespace for type " + qualifiedTypeName);
-                foreach (var entry in lst)
+                var resolvable = lst.Where(static e => e.ClrAssemblyName is { Length: > 0 });
+                foreach (var entry in resolvable)
                 {
                     var asm = Assembly.Load(new AssemblyName(entry.ClrAssemblyName));
                     var resolved = asm.GetType(entry.ClrNamespace + "." + name);
@@ -164,7 +165,8 @@ namespace Avalonia.Markup.Xaml.XamlIl.Runtime
 
                 throw new ArgumentException(
                     $"Unable to resolve type {qualifiedTypeName} from any of the following locations: " +
-                    string.Join(",", lst.Select(e => $"`{e.ClrAssemblyName}:{e.ClrNamespace}.{name}`")));
+                    string.Join(",", resolvable.Select(e => $"`clr-namespace:{e.ClrNamespace};assembly={e.ClrAssemblyName}`")))
+                    { HelpLink = "https://docs.avaloniaui.net/guides/basics/introduction-to-xaml#valid-xaml-namespaces" };
             }
         }
 

src/Markup/Avalonia.Markup/Data/TemplateBinding.cs

@@ -109,7 +109,7 @@ namespace Avalonia.Data
         }
 
         /// <inheritdoc/>
-        void ISetterValue.Initialize(ISetter setter) => _isSetterValue = true;
+        void ISetterValue.Initialize(SetterBase setter) => _isSetterValue = true;
 
         protected override void Subscribed()
         {

src/Windows/Avalonia.Win32.Interop/WinForms/WinFormsAvaloniaControlHost.cs

@@ -22,7 +22,7 @@ namespace Avalonia.Win32.Embedding
             UnmanagedMethods.SetParent(WindowHandle, Handle);
             _root.Prepare();
             if (_root.IsFocused)
-                FocusManager.Instance.Focus(null);
+                _root.FocusManager.ClearFocus();
             _root.GotFocus += RootGotFocus;
 
             FixPosition();

src/Windows/Avalonia.Win32/Input/WindowsKeyboardDevice.cs

@@ -5,7 +5,7 @@ using Avalonia.Win32.Interop;
 
 namespace Avalonia.Win32.Input
 {
-    class WindowsKeyboardDevice : KeyboardDevice
+    internal class WindowsKeyboardDevice : KeyboardDevice
     {
         private readonly byte[] _keyStates = new byte[256];
 

tests/Avalonia.Base.UnitTests/Input/InputElement_Focus.cs

@@ -23,7 +23,7 @@ namespace Avalonia.Base.UnitTests.Input
 
                 target.Focus();
 
-                Assert.Same(target, FocusManager.Instance.Current);
+                Assert.Same(target, root.FocusManager.GetFocusedElement());
             }
         }
         
@@ -39,14 +39,14 @@ namespace Avalonia.Base.UnitTests.Input
                     Child = target = new Button() { IsVisible = false}
                 };
                 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
 
                 target.Focus();
                 
                 Assert.False(target.IsFocused);
                 Assert.False(target.IsKeyboardFocusWithin);
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
         
@@ -67,14 +67,14 @@ namespace Avalonia.Base.UnitTests.Input
                     }
                 };
                 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
 
                 target.Focus();
                 
                 Assert.False(target.IsFocused);
                 Assert.False(target.IsKeyboardFocusWithin);
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -100,11 +100,11 @@ namespace Avalonia.Base.UnitTests.Input
 
                 first.Focus();
 
-                Assert.Same(first, FocusManager.Instance.Current);
+                Assert.Same(first, root.FocusManager.GetFocusedElement());
 
                 second.Focus();
 
-                Assert.Same(first, FocusManager.Instance.Current);
+                Assert.Same(first, root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -120,14 +120,14 @@ namespace Avalonia.Base.UnitTests.Input
                     Child = target = new Button() { IsEnabled = false }
                 };
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
 
                 target.Focus();
 
                 Assert.False(target.IsFocused);
                 Assert.False(target.IsKeyboardFocusWithin);
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -148,14 +148,14 @@ namespace Avalonia.Base.UnitTests.Input
                     }
                 };
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
 
                 target.Focus();
 
                 Assert.False(target.IsFocused);
                 Assert.False(target.IsKeyboardFocusWithin);
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -201,7 +201,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target.Focus();
                 target.IsVisible = false;
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -224,7 +224,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target.Focus();
                 container.IsVisible = false;
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -243,7 +243,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target.Focus();
                 target.IsEnabled = false;
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -266,7 +266,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target.Focus();
                 container.IsEnabled = false;
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -285,7 +285,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target.Focus();
                 root.Child = null;
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
 
@@ -312,13 +312,13 @@ namespace Avalonia.Base.UnitTests.Input
                 target2.ApplyTemplate();
 
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus"));
                 Assert.False(target2.IsFocused);
                 Assert.False(target2.Classes.Contains(":focus"));
 
-                FocusManager.Instance?.Focus(target2, NavigationMethod.Tab);
+                target2.Focus(NavigationMethod.Tab);
                 Assert.False(target1.IsFocused);
                 Assert.False(target1.Classes.Contains(":focus"));
                 Assert.True(target2.IsFocused);
@@ -348,19 +348,19 @@ namespace Avalonia.Base.UnitTests.Input
                 target1.ApplyTemplate();
                 target2.ApplyTemplate();
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.False(target1.Classes.Contains(":focus-visible"));
                 Assert.False(target2.IsFocused);
                 Assert.False(target2.Classes.Contains(":focus-visible"));
 
-                FocusManager.Instance?.Focus(target2, NavigationMethod.Tab);
+                target2.Focus(NavigationMethod.Tab);
                 Assert.False(target1.IsFocused);
                 Assert.False(target1.Classes.Contains(":focus-visible"));
                 Assert.True(target2.IsFocused);
                 Assert.True(target2.Classes.Contains(":focus-visible"));
 
-                FocusManager.Instance?.Focus(target1, NavigationMethod.Directional);
+                target1.Focus(NavigationMethod.Directional);
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus-visible"));
                 Assert.False(target2.IsFocused);
@@ -390,7 +390,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target1.ApplyTemplate();
                 target2.ApplyTemplate();
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus-within"));
                 Assert.True(target1.IsKeyboardFocusWithin);
@@ -425,7 +425,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target1.ApplyTemplate();
                 target2.ApplyTemplate();
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus-within"));
                 Assert.True(target1.IsKeyboardFocusWithin);
@@ -436,7 +436,7 @@ namespace Avalonia.Base.UnitTests.Input
                 Assert.True(root.Classes.Contains(":focus-within"));
                 Assert.True(root.IsKeyboardFocusWithin);
                 
-                FocusManager.Instance?.Focus(target2);
+                target2.Focus();
                 
                 Assert.False(target1.IsFocused);
                 Assert.False(target1.Classes.Contains(":focus-within"));
@@ -478,7 +478,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target1.ApplyTemplate();
                 target2.ApplyTemplate();
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus-within"));
                 Assert.True(target1.IsKeyboardFocusWithin);
@@ -534,7 +534,7 @@ namespace Avalonia.Base.UnitTests.Input
                 target1.ApplyTemplate();
                 target2.ApplyTemplate();
 
-                FocusManager.Instance?.Focus(target1);
+                target1.Focus();
                 Assert.True(target1.IsFocused);
                 Assert.True(target1.Classes.Contains(":focus-within"));
                 Assert.True(target1.IsKeyboardFocusWithin);
@@ -545,7 +545,7 @@ namespace Avalonia.Base.UnitTests.Input
 
                 Assert.Equal(KeyboardDevice.Instance.FocusedElement, target1);
                 
-                FocusManager.Instance?.Focus(target2);
+                target2.Focus();
                 
                 Assert.False(target1.IsFocused);
                 Assert.False(target1.Classes.Contains(":focus-within"));
@@ -578,9 +578,9 @@ namespace Avalonia.Base.UnitTests.Input
                 };
 
                 target.Focus();
-                FocusManager.Instance.Focus(null);
+                root.FocusManager.ClearFocus();
 
-                Assert.Null(FocusManager.Instance.Current);
+                Assert.Null(root.FocusManager.GetFocusedElement());
             }
         }
     }

tests/Avalonia.Base.UnitTests/Input/PointerOverTests.cs

@@ -20,7 +20,9 @@ namespace Avalonia.Base.UnitTests.Input
         [Fact]
         public void Close_Should_Remove_PointerOver()
         {
-            using var app = UnitTestApplication.Start(new TestServices(inputManager: new InputManager()));
+            using var app = UnitTestApplication.Start(new TestServices(
+                inputManager: new InputManager(),
+                focusManager: new FocusManager()));
 
             var renderer = RendererMocks.CreateRenderer();
             var device = CreatePointerDeviceMock().Object;

tests/Avalonia.Base.UnitTests/Media/ColorTests.cs

@@ -335,5 +335,34 @@ namespace Avalonia.Base.UnitTests.Media
                 Assert.True(dataPoint.Item2 == parsedColor);
             }
         }
+
+        [Fact]
+        public void Hsv_To_From_Hsl_Conversion()
+        {
+            // Note that conversion of values more representative of actual colors is not done due to rounding error
+            // It would be necessary to introduce a different equality comparison that accounts for rounding differences in values
+            // This is a result of the math in the conversion itself
+            // RGB doesn't have this problem because it uses whole numbers
+            var data = new Tuple<HsvColor, HslColor>[]
+            {
+                Tuple.Create(new HsvColor(1.0, 0.0, 0.0, 0.0), new HslColor(1.0, 0.0, 0.0, 0.0)),
+                Tuple.Create(new HsvColor(1.0, 359.0, 1.0, 1.0), new HslColor(1.0, 359.0, 1.0, 0.5)),
+
+                Tuple.Create(new HsvColor(1.0, 128.0, 0.0, 0.0), new HslColor(1.0, 128.0, 0.0, 0.0)),
+                Tuple.Create(new HsvColor(1.0, 128.0, 0.0, 1.0), new HslColor(1.0, 128.0, 0.0, 1.0)),
+                Tuple.Create(new HsvColor(1.0, 128.0, 1.0, 1.0), new HslColor(1.0, 128.0, 1.0, 0.5)),
+
+                Tuple.Create(new HsvColor(0.23, 0.5, 1.0, 1.0), new HslColor(0.23, 0.5, 1.0, 0.5)),
+            };
+
+            foreach (var dataPoint in data)
+            {
+                var convertedHsl = dataPoint.Item1.ToHsl();
+                var convertedHsv = dataPoint.Item2.ToHsv();
+
+                Assert.Equal(convertedHsv, dataPoint.Item1);
+                Assert.Equal(convertedHsl, dataPoint.Item2);
+            }
+        }
     }
 }

tests/Avalonia.Benchmarks/Styling/SelectorBenchmark.cs

@@ -37,62 +37,62 @@ namespace Avalonia.Benchmarks.Styling
         }
 
         [Benchmark]
-        public SelectorMatch IsSelector_NoMatch()
+        public void IsSelector_NoMatch()
         {
-            return _isCalendarSelector.Match(_notMatchingControl);
+            _isCalendarSelector.Match(_notMatchingControl);
         }
 
         [Benchmark]
-        public SelectorMatch IsSelector_Match()
+        public void IsSelector_Match()
         {
-            return _isCalendarSelector.Match(_matchingControl);
+            _isCalendarSelector.Match(_matchingControl);
         }
 
         [Benchmark]
-        public SelectorMatch ClassSelector_NoMatch()
+        public void ClassSelector_NoMatch()
         {
-            return _classSelector.Match(_notMatchingControl);
+            _classSelector.Match(_notMatchingControl);
         }
 
         [Benchmark]
-        public SelectorMatch ClassSelector_Match()
+        public void ClassSelector_Match()
         {
-            return _classSelector.Match(_matchingControl);
+            _classSelector.Match(_matchingControl);
         }
 
         [Benchmark]
-        public SelectorMatch OrSelector_One_Match()
+        public void OrSelector_One_Match()
         {
-            return _orSelectorTwo.Match(_matchingControl);
+            _orSelectorTwo.Match(_matchingControl);
         }
 
         [Benchmark]
-        public SelectorMatch OrSelector_Five_Match()
+        public void OrSelector_Five_Match()
         {
-            return _orSelectorFive.Match(_matchingControl);
+            _orSelectorFive.Match(_matchingControl);
         }
     }
 
     internal class AlwaysMatchSelector : Selector
     {
-        public override bool InTemplate => false;
+        internal override bool InTemplate => false;
 
-        public override bool IsCombinator => false;
+        internal override bool IsCombinator => false;
 
-        public override Type TargetType => null;
+        internal override Type TargetType => null;
 
         public override string ToString(Style owner)
         {
             return "Always";
         }
 
-        protected override SelectorMatch Evaluate(StyledElement control, IStyle parent, bool subscribe)
+        private protected override SelectorMatch Evaluate(StyledElement control, IStyle parent, bool subscribe)
         {
             return SelectorMatch.AlwaysThisType;
         }
 
-        protected override Selector MovePrevious() => null;
+        private protected override Selector MovePrevious() => null;
 
-        protected override Selector MovePreviousOrParent() => null;
+        private protected override Selector MovePreviousOrParent() => null;
     }
 }

tests/Avalonia.Controls.UnitTests/FlyoutTests.cs

@@ -288,10 +288,10 @@ namespace Avalonia.Controls.UnitTests
                 window.Show();
 
                 button.Focus();
-                Assert.True(FocusManager.Instance?.Current == button);
+                Assert.True(window.FocusManager.GetFocusedElement() == button);
                 button.Flyout.ShowAt(button);
                 Assert.False(button.IsFocused);
-                Assert.True(FocusManager.Instance?.Current == flyoutTextBox);
+                Assert.True(window.FocusManager.GetFocusedElement() == flyoutTextBox);
             }
         }
 
@@ -322,10 +322,10 @@ namespace Avalonia.Controls.UnitTests
                 window.Content = button;
                 window.Show();
 
-                FocusManager.Instance?.Focus(button);
-                Assert.True(FocusManager.Instance?.Current == button);
+                button.Focus();
+                Assert.True(window.FocusManager.GetFocusedElement() == button);
                 button.Flyout.ShowAt(button);
-                Assert.True(FocusManager.Instance?.Current == button);
+                Assert.True(window.FocusManager.GetFocusedElement() == button);
             }
         }
 

tests/Avalonia.Controls.UnitTests/ItemsControlTests.cs

@@ -576,8 +576,9 @@ namespace Avalonia.Controls.UnitTests
             });
 
             var panel = Assert.IsAssignableFrom<Panel>(target.ItemsPanelRoot);
+            var focusManager = ((IInputRoot)target.VisualRoot!).FocusManager;
 
-            Assert.Equal(panel.Children[1], FocusManager.Instance!.Current);
+            Assert.Equal(panel.Children[1], focusManager?.GetFocusedElement());
         }
 
         [Fact]
@@ -601,8 +602,9 @@ namespace Avalonia.Controls.UnitTests
             });
 
             var panel = Assert.IsAssignableFrom<Panel>(target.ItemsPanelRoot);
+            var focusManager = ((IInputRoot)target.VisualRoot!).FocusManager;
 
-            Assert.Equal(panel.Children[2], FocusManager.Instance!.Current);
+            Assert.Equal(panel.Children[2], focusManager?.GetFocusedElement());
         }
 
         [Fact]

tests/Avalonia.Controls.UnitTests/ListBoxTests.cs

@@ -991,7 +991,7 @@ namespace Avalonia.Controls.UnitTests
             RaiseKeyEvent(button, Key.Tab);
 
             var item = target.ContainerFromIndex(0);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
         }
 
         [Fact]
@@ -1038,17 +1038,17 @@ namespace Avalonia.Controls.UnitTests
             RaiseKeyEvent(button, Key.Tab);
 
             var item = target.ContainerFromIndex(1);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
 
             RaiseKeyEvent(item, Key.Tab);
 
-            Assert.Same(button, FocusManager.Instance.Current);
+            Assert.Same(button, root.FocusManager.GetFocusedElement());
 
             target.Selection.AnchorIndex = 2;
             RaiseKeyEvent(button, Key.Tab);
 
             item = target.ContainerFromIndex(2);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
         }
 
         private static void RaiseKeyEvent(Control target, Key key, KeyModifiers inputModifiers = 0)

tests/Avalonia.Controls.UnitTests/Platform/DefaultMenuInteractionHandlerTests.cs

@@ -267,7 +267,7 @@ namespace Avalonia.Controls.UnitTests.Platform
                 target.KeyDown(item.Object, e);
 
                 parentItem.Verify(x => x.Close());
-                parentItem.Verify(x => x.Focus());
+                parentItem.Verify(x => x.Focus(It.IsAny<NavigationMethod>(), It.IsAny<KeyModifiers>()));
                 Assert.True(e.Handled);
             }
 
@@ -351,7 +351,7 @@ namespace Avalonia.Controls.UnitTests.Platform
                 target.KeyDown(item.Object, e);
 
                 parentItem.Verify(x => x.Close());
-                parentItem.Verify(x => x.Focus());
+                parentItem.Verify(x => x.Focus(It.IsAny<NavigationMethod>(), It.IsAny<KeyModifiers>()));
                 Assert.True(e.Handled);
             }
 

tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs

@@ -642,10 +642,11 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
                 tb.Focus();
 
-                Assert.True(FocusManager.Instance?.Current == tb);
+                var focusManager = TopLevel.GetTopLevel(tb)!.FocusManager;
+                tb = Assert.IsType<TextBox>(focusManager.GetFocusedElement());
 
                 //Ensure focus remains in the popup
-                var nextFocus = KeyboardNavigationHandler.GetNext(FocusManager.Instance.Current, NavigationDirection.Next);
+                var nextFocus = KeyboardNavigationHandler.GetNext(tb, NavigationDirection.Next);
 
                 Assert.True(nextFocus == b);
 
@@ -684,7 +685,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
                 p.Close();
 
-                var focus = FocusManager.Instance?.Current;
+                var focusManager = window.FocusManager;
+                var focus = focusManager.GetFocusedElement();
                 Assert.True(focus == window);
             }
         }
@@ -723,7 +725,8 @@ namespace Avalonia.Controls.UnitTests.Primitives
 
                 windowTB.Focus();
 
-                var focus = FocusManager.Instance?.Current;
+                var focusManager = window.FocusManager;
+                var focus = focusManager.GetFocusedElement();
 
                 Assert.True(focus == windowTB);
 

tests/Avalonia.Controls.UnitTests/TabControlTests.cs

@@ -461,7 +461,7 @@ namespace Avalonia.Controls.UnitTests
             RaiseKeyEvent(button, Key.Tab);
 
             var item = target.ContainerFromIndex(0);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
         }
 
         [Fact]
@@ -513,17 +513,17 @@ namespace Avalonia.Controls.UnitTests
             RaiseKeyEvent(button, Key.Tab);
 
             var item = target.ContainerFromIndex(1);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
 
             RaiseKeyEvent(item, Key.Tab);
 
-            Assert.Same(button, FocusManager.Instance.Current);
+            Assert.Same(button, root.FocusManager.GetFocusedElement());
 
             target.Selection.AnchorIndex = 2;
             RaiseKeyEvent(button, Key.Tab);
 
             item = target.ContainerFromIndex(2);
-            Assert.Same(item, FocusManager.Instance.Current);
+            Assert.Same(item, root.FocusManager.GetFocusedElement());
         }
 
         private static IControlTemplate TabControlTemplate()

tests/Avalonia.Controls.UnitTests/TreeViewTests.cs

@@ -969,7 +969,6 @@ namespace Avalonia.Controls.UnitTests
         public void Keyboard_Navigation_Should_Move_To_Last_Selected_Node()
         {
             using var app = Start();
-            var focus = FocusManager.Instance!;
             var navigation = AvaloniaLocator.Current.GetRequiredService<IKeyboardNavigationHandler>();
             var data = CreateTestTreeData();
 
@@ -984,6 +983,7 @@ namespace Avalonia.Controls.UnitTests
             {
                 Children = { target, button },
             });
+            var focus = root.FocusManager;
 
             root.LayoutManager.ExecuteInitialLayoutPass();
             ExpandAll(target);
@@ -994,20 +994,19 @@ namespace Avalonia.Controls.UnitTests
 
             target.SelectedItem = item;
             node.Focus();
-            Assert.Same(node, focus.Current);
+            Assert.Same(node, focus.GetFocusedElement());
 
-            navigation.Move(focus.Current!, NavigationDirection.Next);
-            Assert.Same(button, focus.Current);
+            navigation.Move(focus.GetFocusedElement()!, NavigationDirection.Next);
+            Assert.Same(button, focus.GetFocusedElement());
 
-            navigation.Move(focus.Current!, NavigationDirection.Next);
-            Assert.Same(node, focus.Current);
+            navigation.Move(focus.GetFocusedElement()!, NavigationDirection.Next);
+            Assert.Same(node, focus.GetFocusedElement());
         }
 
         [Fact]
         public void Keyboard_Navigation_Should_Not_Crash_If_Selected_Item_Is_not_In_Tree()
         {
             using var app = Start();
-            var focus = FocusManager.Instance!;
             var data = CreateTestTreeData();
 
             var selectedNode = new Node { Value = "Out of Tree Selected Item" };
@@ -1025,6 +1024,7 @@ namespace Avalonia.Controls.UnitTests
             {
                 Children = { target, button },
             });
+            var focus = root.FocusManager;
 
             root.LayoutManager.ExecuteInitialLayoutPass();
             ExpandAll(target);
@@ -1035,7 +1035,7 @@ namespace Avalonia.Controls.UnitTests
 
             target.SelectedItem = selectedNode;
             node.Focus();
-            Assert.Same(node, focus.Current);
+            Assert.Same(node, focus.GetFocusedElement());
         }
 
         [Fact]

tests/Avalonia.Controls.UnitTests/VirtualizingStackPanelTests.cs

@@ -657,6 +657,40 @@ namespace Avalonia.Controls.UnitTests
             root.LayoutManager.ExecuteLayoutPass();
         }
 
+        [Fact]
+        public void ScrollIntoView_On_Effectively_Invisible_Panel_Does_Not_Create_Ghost_Elements()
+        {
+            var items = new[] { "foo", "bar", "baz" };
+            var (target, _, itemsControl) = CreateUnrootedTarget(items: items);
+            var container = new Decorator { Margin = new Thickness(100), Child = itemsControl };
+            var root = new TestRoot(true, container);
+
+            root.LayoutManager.ExecuteInitialLayoutPass();
+
+            // Clear the items and do a layout to recycle all elements.
+            itemsControl.ItemsSource = null;
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // Should have no realized elements and 3 unrealized elements.
+            Assert.Equal(0, target.GetRealizedElements().Count);
+            Assert.Equal(3, target.Children.Count);
+
+            // Make the panel effectively invisible and set items.
+            container.IsVisible = false;
+            itemsControl.ItemsSource = items;
+
+            // Try to scroll into view while effectively invisible.
+            target.ScrollIntoView(0);
+
+            // Make the panel visible and layout.
+            container.IsVisible = true;
+            root.LayoutManager.ExecuteLayoutPass();
+
+            // Should have 3 realized elements and no unrealized elements.
+            Assert.Equal(3, target.GetRealizedElements().Count);
+            Assert.Equal(3, target.Children.Count);
+        }
+
         private static IReadOnlyList<int> GetRealizedIndexes(VirtualizingStackPanel target, ItemsControl itemsControl)
         {
             return target.GetRealizedElements()

tests/Avalonia.LeakTests/ControlTests.cs

@@ -561,7 +561,7 @@ namespace Avalonia.LeakTests
                 var window = new Window { Focusable = true };
                 window.Show();
 
-                Assert.Same(window, FocusManager.Instance.Current);
+                Assert.Same(window, window.FocusManager.GetFocusedElement());
 
                 // Context menu in resources means the baseline may not be 0.
                 var initialMenuCount = 0;
@@ -608,7 +608,7 @@ namespace Avalonia.LeakTests
                 var window = new Window { Focusable = true };
                 window.Show();
 
-                Assert.Same(window, FocusManager.Instance.Current);
+                Assert.Same(window, window.FocusManager.GetFocusedElement());
 
                 // Context menu in resources means the baseline may not be 0.
                 var initialMenuCount = 0;

tests/Avalonia.UnitTests/StyleHelpers.cs

@@ -6,9 +6,9 @@ namespace Avalonia.UnitTests
 {
     public static class StyleHelpers
     {
-        public static SelectorMatchResult TryAttach(Style style, StyledElement element, object? host = null)
+        public static void TryAttach(Style style, StyledElement element, object? host = null)
         {
-            return style.TryAttach(element, host ?? element, PropertyStore.FrameType.Style);
+            style.TryAttach(element, host ?? element, PropertyStore.FrameType.Style);
         }
     }
 }

tests/Avalonia.UnitTests/TestRoot.cs

@@ -54,6 +54,7 @@ namespace Avalonia.UnitTests
         public IAccessKeyHandler AccessKeyHandler => null;
 
         public IKeyboardNavigationHandler KeyboardNavigationHandler => null;
+        public IFocusManager FocusManager => AvaloniaLocator.Current.GetService<IFocusManager>();
 
         public IInputElement PointerOverElement { get; set; }