Merge branch 'master' into transform-3d

build/ApiCompatAttributeExcludeList.txt

@@ -0,0 +1,2 @@
+T:Avalonia.Metadata.NotClientImplementableAttribute
+T:Avalonia.Metadata.UnstableAttribute

build/CoreLibraries.props

@@ -3,8 +3,6 @@
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Base/Avalonia.Base.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Controls/Avalonia.Controls.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj" />
-      <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Themes.Default/Avalonia.Themes.Default.csproj" />
-      <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Themes.Fluent/Avalonia.Themes.Fluent.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.OpenGL/Avalonia.OpenGL.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Avalonia.Dialogs/Avalonia.Dialogs.csproj" />
       <ProjectReference Include="$(MSBuildThisFileDirectory)/../src/Markup/Avalonia.Markup/Avalonia.Markup.csproj" />

native/Avalonia.Native/inc/rendertarget.h

@@ -1,3 +1,8 @@
+#pragma once
+
+#include "com.h"
+#include "comimpl.h"
+#include "avalonia-native.h"
 
 @protocol IRenderTarget
 -(void) setNewLayer: (CALayer*) layer;

native/Avalonia.Native/src/OSX/AutoFitContentView.h

@@ -3,8 +3,10 @@
 // Copyright (c) 2022 Avalonia. All rights reserved.
 //
 
+#pragma once
+
 #import <Foundation/Foundation.h>
-#import "avalonia-native.h"
+#include "avalonia-native.h"
 
 @interface AutoFitContentView : NSView
 -(AutoFitContentView* _Nonnull) initWithContent: (NSView* _Nonnull) content;

native/Avalonia.Native/src/OSX/AutoFitContentView.mm

@@ -4,7 +4,9 @@
 //
 
 #include "AvnView.h"
-#import "AutoFitContentView.h"
+#include "AutoFitContentView.h"
+#include "WindowInterfaces.h"
+#include "WindowProtocol.h"
 
 @implementation AutoFitContentView
 {
@@ -83,7 +85,7 @@
     _settingSize = true;
     [super setFrameSize:newSize];
 
-    auto window = objc_cast<AvnWindow>([self window]);
+    auto window = (id <AvnWindowProtocol>) [self window];
 
     // TODO get actual titlebar size
 

native/Avalonia.Native/src/OSX/Avalonia.Native.OSX.xcodeproj/project.pbxproj

@@ -9,16 +9,22 @@
 /* Begin PBXBuildFile section */
 		18391068E48EF96E3DB5FDAB /* ResizeScope.mm in Sources */ = {isa = PBXBuildFile; fileRef = 18391E45702740FE9DD69695 /* ResizeScope.mm */; };
 		1839125F057B0A4EB1760058 /* WindowImpl.mm in Sources */ = {isa = PBXBuildFile; fileRef = 183919BF108EB72A029F7671 /* WindowImpl.mm */; };
+		183914E50CF6D2EFC1667F7C /* WindowInterfaces.h in Headers */ = {isa = PBXBuildFile; fileRef = 18391DB45C7D892E61BF388C /* WindowInterfaces.h */; };
+		1839151F32D1BB1AB51A7BB6 /* AvnPanelWindow.mm in Sources */ = {isa = PBXBuildFile; fileRef = 18391884C7476DA4E53A492D /* AvnPanelWindow.mm */; };
 		183916173528EC2737DBE5E1 /* WindowBaseImpl.h in Headers */ = {isa = PBXBuildFile; fileRef = 183915BFF0E234CD3604A7CD /* WindowBaseImpl.h */; };
 		1839171DCC651B0638603AC4 /* INSWindowHolder.h in Headers */ = {isa = PBXBuildFile; fileRef = 18391BBB7782C296D424071F /* INSWindowHolder.h */; };
 		1839179A55FC1421BEE83330 /* WindowBaseImpl.mm in Sources */ = {isa = PBXBuildFile; fileRef = 18391676ECF0E983F4964357 /* WindowBaseImpl.mm */; };
 		183919D91DB9AAB5D700C2EA /* WindowImpl.h in Headers */ = {isa = PBXBuildFile; fileRef = 18391CD090AA776E7E841AC9 /* WindowImpl.h */; };
 		18391AA7E0BBA74D184C5734 /* AutoFitContentView.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1839166350F32661F3ABD70F /* AutoFitContentView.mm */; };
+		18391AC16726CBC45856233B /* AvnWindow.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1839155B28B20FFB672D29C6 /* AvnWindow.mm */; };
+		18391AC65ADD7DDD33FBE737 /* PopupImpl.h in Headers */ = {isa = PBXBuildFile; fileRef = 183910513F396141938832B5 /* PopupImpl.h */; };
 		18391C28BF1823B5464FDD36 /* ResizeScope.h in Headers */ = {isa = PBXBuildFile; fileRef = 1839171D898F9BFC1373631A /* ResizeScope.h */; };
 		18391CF07316F819E76B617C /* IWindowStateChanged.h in Headers */ = {isa = PBXBuildFile; fileRef = 183913C6BFD6856BD42D19FD /* IWindowStateChanged.h */; };
 		18391D4EB311BC7EF8B8C0A6 /* AvnView.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1839132D0E2454D911F1D1F9 /* AvnView.mm */; };
+		18391D8CD1756DC858DC1A09 /* PopupImpl.mm in Sources */ = {isa = PBXBuildFile; fileRef = 18391BB698579F40F1783F31 /* PopupImpl.mm */; };
 		18391E1381E2D5BFD60265A9 /* AutoFitContentView.h in Headers */ = {isa = PBXBuildFile; fileRef = 18391654EF0E7AB3D3AB4071 /* AutoFitContentView.h */; };
 		18391ED5F611FF62C45F196D /* AvnView.h in Headers */ = {isa = PBXBuildFile; fileRef = 18391D1669284AD2EC9E866A /* AvnView.h */; };
+		18391F1E2411C79405A9943A /* WindowProtocol.h in Headers */ = {isa = PBXBuildFile; fileRef = 1839122E037567BDD1D09DEB /* WindowProtocol.h */; };
 		1A002B9E232135EE00021753 /* app.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1A002B9D232135EE00021753 /* app.mm */; };
 		1A1852DC23E05814008F0DED /* deadlock.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1A1852DB23E05814008F0DED /* deadlock.mm */; };
 		1A3E5EA823E9E83B00EDE661 /* rendertarget.mm in Sources */ = {isa = PBXBuildFile; fileRef = 1A3E5EA723E9E83B00EDE661 /* rendertarget.mm */; };
@@ -40,24 +46,29 @@
 		AB00E4F72147CA920032A60A /* main.mm in Sources */ = {isa = PBXBuildFile; fileRef = AB00E4F62147CA920032A60A /* main.mm */; };
 		AB1E522C217613570091CD71 /* OpenGL.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = AB1E522B217613570091CD71 /* OpenGL.framework */; };
 		AB661C1E2148230F00291242 /* AppKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = AB661C1D2148230F00291242 /* AppKit.framework */; };
-		AB661C202148286E00291242 /* window.mm in Sources */ = {isa = PBXBuildFile; fileRef = AB661C1F2148286E00291242 /* window.mm */; };
 		AB8F7D6B21482D7F0057DBA5 /* platformthreading.mm in Sources */ = {isa = PBXBuildFile; fileRef = AB8F7D6A21482D7F0057DBA5 /* platformthreading.mm */; };
 		BC11A5BE2608D58F0017BAD0 /* automation.h in Headers */ = {isa = PBXBuildFile; fileRef = BC11A5BC2608D58F0017BAD0 /* automation.h */; };
 		BC11A5BF2608D58F0017BAD0 /* automation.mm in Sources */ = {isa = PBXBuildFile; fileRef = BC11A5BD2608D58F0017BAD0 /* automation.mm */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
+		183910513F396141938832B5 /* PopupImpl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = PopupImpl.h; sourceTree = "<group>"; };
+		1839122E037567BDD1D09DEB /* WindowProtocol.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WindowProtocol.h; sourceTree = "<group>"; };
 		1839132D0E2454D911F1D1F9 /* AvnView.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AvnView.mm; sourceTree = "<group>"; };
 		183913C6BFD6856BD42D19FD /* IWindowStateChanged.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IWindowStateChanged.h; sourceTree = "<group>"; };
+		1839155B28B20FFB672D29C6 /* AvnWindow.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AvnWindow.mm; sourceTree = "<group>"; };
 		183915BFF0E234CD3604A7CD /* WindowBaseImpl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WindowBaseImpl.h; sourceTree = "<group>"; };
 		18391654EF0E7AB3D3AB4071 /* AutoFitContentView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AutoFitContentView.h; sourceTree = "<group>"; };
 		1839166350F32661F3ABD70F /* AutoFitContentView.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AutoFitContentView.mm; sourceTree = "<group>"; };
 		18391676ECF0E983F4964357 /* WindowBaseImpl.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = WindowBaseImpl.mm; sourceTree = "<group>"; };
 		1839171D898F9BFC1373631A /* ResizeScope.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ResizeScope.h; sourceTree = "<group>"; };
+		18391884C7476DA4E53A492D /* AvnPanelWindow.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AvnPanelWindow.mm; sourceTree = "<group>"; };
 		183919BF108EB72A029F7671 /* WindowImpl.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = WindowImpl.mm; sourceTree = "<group>"; };
+		18391BB698579F40F1783F31 /* PopupImpl.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = PopupImpl.mm; sourceTree = "<group>"; };
 		18391BBB7782C296D424071F /* INSWindowHolder.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = INSWindowHolder.h; sourceTree = "<group>"; };
 		18391CD090AA776E7E841AC9 /* WindowImpl.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WindowImpl.h; sourceTree = "<group>"; };
 		18391D1669284AD2EC9E866A /* AvnView.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AvnView.h; sourceTree = "<group>"; };
+		18391DB45C7D892E61BF388C /* WindowInterfaces.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = WindowInterfaces.h; sourceTree = "<group>"; };
 		18391E45702740FE9DD69695 /* ResizeScope.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ResizeScope.mm; sourceTree = "<group>"; };
 		1A002B9D232135EE00021753 /* app.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = app.mm; sourceTree = "<group>"; };
 		1A1852DB23E05814008F0DED /* deadlock.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = deadlock.mm; sourceTree = "<group>"; };
@@ -72,7 +83,6 @@
 		37A4E71A2178846A00EACBCD /* headers */ = {isa = PBXFileReference; lastKnownFileType = folder; name = headers; path = ../../inc; sourceTree = "<group>"; };
 		37A517B22159597E00FBA241 /* Screens.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = Screens.mm; sourceTree = "<group>"; };
 		37C09D8721580FE4006A6758 /* SystemDialogs.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = SystemDialogs.mm; sourceTree = "<group>"; };
-		37C09D8A21581EF2006A6758 /* window.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = window.h; sourceTree = "<group>"; };
 		37DDA9AF219330F8002E132B /* AvnString.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; path = AvnString.mm; sourceTree = "<group>"; };
 		37DDA9B121933371002E132B /* AvnString.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = AvnString.h; sourceTree = "<group>"; };
 		37E2330E21583241000CB7E2 /* KeyTransform.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = KeyTransform.mm; sourceTree = "<group>"; };
@@ -86,7 +96,6 @@
 		AB00E4F62147CA920032A60A /* main.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = main.mm; sourceTree = "<group>"; };
 		AB1E522B217613570091CD71 /* OpenGL.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = OpenGL.framework; path = System/Library/Frameworks/OpenGL.framework; sourceTree = SDKROOT; };
 		AB661C1D2148230F00291242 /* AppKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AppKit.framework; path = System/Library/Frameworks/AppKit.framework; sourceTree = SDKROOT; };
-		AB661C1F2148286E00291242 /* window.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = window.mm; sourceTree = "<group>"; };
 		AB661C212148288600291242 /* common.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = common.h; sourceTree = "<group>"; };
 		AB7A61EF2147C815003C5833 /* libAvalonia.Native.OSX.dylib */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.dylib"; includeInIndex = 0; path = libAvalonia.Native.OSX.dylib; sourceTree = BUILT_PRODUCTS_DIR; };
 		AB8F7D6A21482D7F0057DBA5 /* platformthreading.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = platformthreading.mm; sourceTree = "<group>"; };
@@ -142,8 +151,6 @@
 				AB661C212148288600291242 /* common.h */,
 				379860FE214DA0C000CD0246 /* KeyTransform.h */,
 				37E2330E21583241000CB7E2 /* KeyTransform.mm */,
-				AB661C1F2148286E00291242 /* window.mm */,
-				37C09D8A21581EF2006A6758 /* window.h */,
 				AB00E4F62147CA920032A60A /* main.mm */,
 				37155CE3233C00EB0034DCE9 /* menu.h */,
 				520624B222973F4100C4DCEF /* menu.mm */,
@@ -166,6 +173,12 @@
 				18391D1669284AD2EC9E866A /* AvnView.h */,
 				1839166350F32661F3ABD70F /* AutoFitContentView.mm */,
 				18391654EF0E7AB3D3AB4071 /* AutoFitContentView.h */,
+				18391884C7476DA4E53A492D /* AvnPanelWindow.mm */,
+				1839122E037567BDD1D09DEB /* WindowProtocol.h */,
+				1839155B28B20FFB672D29C6 /* AvnWindow.mm */,
+				18391DB45C7D892E61BF388C /* WindowInterfaces.h */,
+				18391BB698579F40F1783F31 /* PopupImpl.mm */,
+				183910513F396141938832B5 /* PopupImpl.h */,
 			);
 			sourceTree = "<group>";
 		};
@@ -193,6 +206,9 @@
 				18391C28BF1823B5464FDD36 /* ResizeScope.h in Headers */,
 				18391ED5F611FF62C45F196D /* AvnView.h in Headers */,
 				18391E1381E2D5BFD60265A9 /* AutoFitContentView.h in Headers */,
+				18391F1E2411C79405A9943A /* WindowProtocol.h in Headers */,
+				183914E50CF6D2EFC1667F7C /* WindowInterfaces.h in Headers */,
+				18391AC65ADD7DDD33FBE737 /* PopupImpl.h in Headers */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -271,12 +287,14 @@
 				1A465D10246AB61600C5858B /* dnd.mm in Sources */,
 				AB00E4F72147CA920032A60A /* main.mm in Sources */,
 				37C09D8821580FE4006A6758 /* SystemDialogs.mm in Sources */,
-				AB661C202148286E00291242 /* window.mm in Sources */,
 				1839179A55FC1421BEE83330 /* WindowBaseImpl.mm in Sources */,
 				1839125F057B0A4EB1760058 /* WindowImpl.mm in Sources */,
 				18391068E48EF96E3DB5FDAB /* ResizeScope.mm in Sources */,
 				18391D4EB311BC7EF8B8C0A6 /* AvnView.mm in Sources */,
 				18391AA7E0BBA74D184C5734 /* AutoFitContentView.mm in Sources */,
+				1839151F32D1BB1AB51A7BB6 /* AvnPanelWindow.mm in Sources */,
+				18391AC16726CBC45856233B /* AvnWindow.mm in Sources */,
+				18391D8CD1756DC858DC1A09 /* PopupImpl.mm in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

native/Avalonia.Native/src/OSX/AvnPanelWindow.mm

@@ -0,0 +1,11 @@
+//
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
+
+#pragma once
+
+#define IS_NSPANEL
+
+#include "AvnWindow.mm"
+

native/Avalonia.Native/src/OSX/AvnView.h

@@ -2,17 +2,15 @@
 // Created by Dan Walmsley on 05/05/2022.
 // Copyright (c) 2022 Avalonia. All rights reserved.
 //
-
+#pragma once
 #import <Foundation/Foundation.h>
 
 
 #import <Foundation/Foundation.h>
 #import <AppKit/AppKit.h>
-#include "window.h"
+#include "common.h"
-#import "comimpl.h"
+#include "WindowImpl.h"
-#import "common.h"
+#include "KeyTransform.h"
-#import "WindowImpl.h"
-#import "KeyTransform.h"
 
 @class AvnAccessibilityElement;
 

native/Avalonia.Native/src/OSX/AvnView.mm

@@ -4,8 +4,9 @@
 //
 
 #import <AppKit/AppKit.h>
-#import "AvnView.h"
+#include "AvnView.h"
 #include "automation.h"
+#import "WindowInterfaces.h"
 
 @implementation AvnView
 {
@@ -194,7 +195,12 @@
 
 - (bool) ignoreUserInput:(bool)trigerInputWhenDisabled
 {
-    auto parentWindow = objc_cast<AvnWindow>([self window]);
+    if(_parent == nullptr)
+    {
+        return TRUE;
+    }
+
+    auto parentWindow = _parent->GetWindowProtocol();
 
     if(parentWindow == nil || ![parentWindow shouldTryToHandleEvents])
     {

native/Avalonia.Native/src/OSX/window.mm → native/Avalonia.Native/src/OSX/AvnWindow.mm

@@ -1,18 +1,37 @@
+//
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
+
+
+#import <AppKit/AppKit.h>
+#import "WindowProtocol.h"
+#import "WindowBaseImpl.h"
+
+#ifdef IS_NSPANEL
+#define BASE_CLASS NSPanel
+#define CLASS_NAME AvnPanel
+#else
+#define BASE_CLASS NSWindow
+#define CLASS_NAME AvnWindow
+#endif
+
 #import <AppKit/AppKit.h>
 #include "common.h"
-#import "window.h"
 #include "menu.h"
 #include "automation.h"
-#import "WindowBaseImpl.h"
+#include "WindowBaseImpl.h"
 #include "WindowImpl.h"
 #include "AvnView.h"
+#include "WindowInterfaces.h"
+#include "PopupImpl.h"
 
-@implementation AvnWindow
+@implementation CLASS_NAME
 {
     ComPtr<WindowBaseImpl> _parent;
-    bool _canBecomeKeyAndMain;
     bool _closed;
     bool _isEnabled;
+    bool _canBecomeKeyWindow;
     bool _isExtended;
     AvnMenu* _menu;
 }
@@ -66,7 +85,7 @@
 - (void)pollModalSession:(nonnull NSModalSession)session
 {
     auto response = [NSApp runModalSession:session];
-    
+
     if(response == NSModalResponseContinue)
     {
         dispatch_async(dispatch_get_main_queue(), ^{
@@ -85,18 +104,18 @@
     if(_menu != nullptr)
     {
         auto appMenuItem = ::GetAppMenuItem();
-        
+
         if(appMenuItem != nullptr)
         {
             auto appMenu = [appMenuItem menu];
-            
+
             [appMenu removeItem:appMenuItem];
-            
+
             [_menu insertItem:appMenuItem atIndex:0];
-            
+
             [_menu setHasGlobalMenuItem:true];
         }
-        
+
         [NSApp setMenu:_menu];
     }
     else
@@ -108,22 +127,22 @@
 -(void) showAppMenuOnly
 {
     auto appMenuItem = ::GetAppMenuItem();
-    
+
     if(appMenuItem != nullptr)
     {
         auto appMenu = ::GetAppMenu();
-        
+
         auto nativeAppMenu = dynamic_cast<AvnAppMenu*>(appMenu);
-        
+
         [[appMenuItem menu] removeItem:appMenuItem];
-        
+
         if(_menu != nullptr)
         {
             [_menu setHasGlobalMenuItem:false];
         }
-        
+
         [nativeAppMenu->GetNative() addItem:appMenuItem];
-        
+
         [NSApp setMenu:nativeAppMenu->GetNative()];
     }
 }
@@ -134,40 +153,45 @@
     {
         menu = [AvnMenu new];
     }
-    
+
     _menu = menu;
 }
 
--(void) setCanBecomeKeyAndMain
+-(CLASS_NAME*)  initWithParent: (WindowBaseImpl*) parent contentRect: (NSRect)contentRect styleMask: (NSWindowStyleMask)styleMask;
 {
-    _canBecomeKeyAndMain = true;
+    // https://jameshfisher.com/2020/07/10/why-is-the-contentrect-of-my-nswindow-ignored/
-}
+    // create nswindow with specific contentRect, otherwise we wont be able to resize the window
+    // until several ms after the window is physically on the screen.
+    self = [super initWithContentRect:contentRect styleMask: styleMask backing:NSBackingStoreBuffered defer:false];
 
--(AvnWindow*)  initWithParent: (WindowBaseImpl*) parent
-{
-    self = [super init];
     [self setReleasedWhenClosed:false];
     _parent = parent;
     [self setDelegate:self];
     _closed = false;
     _isEnabled = true;
-    
+
     [self backingScaleFactor];
     [self setOpaque:NO];
     [self setBackgroundColor: [NSColor clearColor]];
+
     _isExtended = false;
+
+#ifdef IS_NSPANEL
+    [self setCollectionBehavior:NSWindowCollectionBehaviorCanJoinAllSpaces|NSWindowCollectionBehaviorFullScreenAuxiliary];
+#endif
+
     return self;
 }
 
 - (BOOL)windowShouldClose:(NSWindow *)sender
 {
     auto window = dynamic_cast<WindowImpl*>(_parent.getRaw());
-    
+
     if(window != nullptr)
     {
         return !window->WindowEvents->Closing();
     }
-    
+
     return true;
 }
 
@@ -176,6 +200,8 @@
     [self backingScaleFactor];
 }
 
+
+
 - (void)windowWillClose:(NSNotification *)notification
 {
     _closed = true;
@@ -191,27 +217,38 @@
 
 -(BOOL)canBecomeKeyWindow
 {
-    if (_canBecomeKeyAndMain)
+    if(_canBecomeKeyWindow)
     {
         // If the window has a child window being shown as a dialog then don't allow it to become the key window.
         for(NSWindow* uch in [self childWindows])
         {
-            auto ch = objc_cast<AvnWindow>(uch);
+            if (![uch conformsToProtocol:@protocol(AvnWindowProtocol)])
-            if(ch == nil)
+            {
                 continue;
-            if (ch.isDialog)
+            }
+
+            id <AvnWindowProtocol> ch = (id <AvnWindowProtocol>) uch;
+
+            if(ch.isDialog)
                 return false;
         }
-        
+
         return true;
     }
     
     return false;
 }
 
+#ifndef IS_NSPANEL
 -(BOOL)canBecomeMainWindow
 {
-    return _canBecomeKeyAndMain;
+    return true;
+}
+#endif
+
+-(void)setCanBecomeKeyWindow:(bool)value
+{
+    _canBecomeKeyWindow = value;
 }
 
 -(bool)shouldTryToHandleEvents
@@ -227,7 +264,7 @@
 -(void)becomeKeyWindow
 {
     [self showWindowMenuWithAppMenu];
-    
+
     if(_parent != nullptr)
     {
         _parent->BaseEvents->Activated();
@@ -238,7 +275,8 @@
 
 -(void) restoreParentWindow;
 {
-    auto parent = objc_cast<AvnWindow>([self parentWindow]);
+    auto parent = [self parentWindow];
+
     if(parent != nil)
     {
         [parent removeChildWindow:self];
@@ -248,7 +286,7 @@
 - (void)windowDidMiniaturize:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->WindowStateChanged();
@@ -258,7 +296,7 @@
 - (void)windowDidDeminiaturize:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->WindowStateChanged();
@@ -268,7 +306,7 @@
 - (void)windowDidResize:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->WindowStateChanged();
@@ -278,7 +316,7 @@
 - (void)windowWillExitFullScreen:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->StartStateTransition();
@@ -288,22 +326,22 @@
 - (void)windowDidExitFullScreen:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->EndStateTransition();
-        
+
         if(parent->Decorations() != SystemDecorationsFull && parent->WindowState() == Maximized)
         {
             NSRect screenRect = [[self screen] visibleFrame];
             [self setFrame:screenRect display:YES];
         }
-        
+
         if(parent->WindowState() == Minimized)
         {
             [self miniaturize:nullptr];
         }
-        
+
         parent->WindowStateChanged();
     }
 }
@@ -311,7 +349,7 @@
 - (void)windowWillEnterFullScreen:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->StartStateTransition();
@@ -321,7 +359,7 @@
 - (void)windowDidEnterFullScreen:(NSNotification *)notification
 {
     auto parent = dynamic_cast<IWindowStateChanged*>(_parent.operator->());
-    
+
     if(parent != nullptr)
     {
         parent->EndStateTransition();
@@ -338,28 +376,33 @@
 {
     if(_parent)
         _parent->BaseEvents->Deactivated();
-    
+
     [self showAppMenuOnly];
-    
+
     [super resignKeyWindow];
 }
 
 - (void)windowDidMove:(NSNotification *)notification
 {
     AvnPoint position;
-    
+
     if(_parent != nullptr)
     {
         auto cparent = dynamic_cast<WindowImpl*>(_parent.getRaw());
-        
+
         if(cparent != nullptr)
         {
+            if(!cparent->IsShown())
+            {
+                return;
+            }
+
             if(cparent->WindowState() == Maximized)
             {
                 cparent->SetWindowState(Normal);
             }
         }
-        
+
         _parent->GetPosition(&position);
         _parent->BaseEvents->PositionChanged(position);
     }
@@ -374,7 +417,7 @@
 - (void)sendEvent:(NSEvent *)event
 {
     [super sendEvent:event];
-    
+
     /// This is to detect non-client clicks. This can only be done on Windows... not popups, hence the dynamic_cast.
     if(_parent != nullptr && dynamic_cast<WindowImpl*>(_parent.getRaw()) != nullptr)
     {
@@ -385,95 +428,39 @@
                 AvnView* view = _parent->View;
                 NSPoint windowPoint = [event locationInWindow];
                 NSPoint viewPoint = [view convertPoint:windowPoint fromView:nil];
-                
+
                 if (!NSPointInRect(viewPoint, view.bounds))
                 {
                     auto avnPoint = [AvnView toAvnPoint:windowPoint];
                     auto point = [self translateLocalPoint:avnPoint];
                     AvnVector delta = { 0, 0 };
-                   
+
                     _parent->BaseEvents->RawMouseEvent(NonClientLeftButtonDown, static_cast<uint32>([event timestamp] * 1000), AvnInputModifiersNone, point, delta);
                 }
             }
-            break;
+                break;
-                
+
             case NSEventTypeMouseEntered:
             {
                 _parent->UpdateCursor();
             }
-            break;
+                break;
-                
+
             case NSEventTypeMouseExited:
             {
                 [[NSCursor arrowCursor] set];
             }
-            break;
+                break;
-                
+
             default:
                 break;
         }
     }
 }
 
-@end
+- (void)disconnectParent {
-
+    _parent = nullptr;
-class PopupImpl : public virtual WindowBaseImpl, public IAvnPopup
-{
-private:
-    BEGIN_INTERFACE_MAP()
-    INHERIT_INTERFACE_MAP(WindowBaseImpl)
-    INTERFACE_MAP_ENTRY(IAvnPopup, IID_IAvnPopup)
-    END_INTERFACE_MAP()
-    virtual ~PopupImpl(){}
-    ComPtr<IAvnWindowEvents> WindowEvents;
-    PopupImpl(IAvnWindowEvents* events, IAvnGlContext* gl) : WindowBaseImpl(events, gl)
-    {
-        WindowEvents = events;
-        [Window setLevel:NSPopUpMenuWindowLevel];
-    }
-protected:
-    virtual NSWindowStyleMask GetStyle() override
-    {
-        return NSWindowStyleMaskBorderless;
-    }
-    
-    virtual HRESULT Resize(double x, double y, AvnPlatformResizeReason reason) override
-    {
-        START_COM_CALL;
-        
-        @autoreleasepool
-        {
-            if (Window != nullptr)
-            {
-                [Window setContentSize:NSSize{x, y}];
-            
-                [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(lastPositionSet))];
-            }
-            
-            return S_OK;
-        }
-    }
-public:
-    virtual bool ShouldTakeFocusOnShow() override
-    {
-        return false;
-    }
-};
-
-extern IAvnPopup* CreateAvnPopup(IAvnWindowEvents*events, IAvnGlContext* gl)
-{
-    @autoreleasepool
-    {
-        IAvnPopup* ptr = dynamic_cast<IAvnPopup*>(new PopupImpl(events, gl));
-        return ptr;
-    }
 }
 
-extern IAvnWindow* CreateAvnWindow(IAvnWindowEvents*events, IAvnGlContext* gl)
+@end
-{
+
-    @autoreleasepool
-    {
-        IAvnWindow* ptr = (IAvnWindow*)new WindowImpl(events, gl);
-        return ptr;
-    }
-}

native/Avalonia.Native/src/OSX/INSWindowHolder.h

@@ -10,8 +10,8 @@
 
 struct INSWindowHolder
 {
-    virtual AvnWindow* _Nonnull GetNSWindow () = 0;
+    virtual NSWindow* _Nonnull GetNSWindow () = 0;
-    virtual AvnView* _Nonnull GetNSView () = 0;
+    virtual NSView* _Nonnull GetNSView () = 0;
 };
 
 #endif //AVALONIA_NATIVE_OSX_INSWINDOWHOLDER_H

native/Avalonia.Native/src/OSX/PopupImpl.h

@@ -0,0 +1,9 @@
+//
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
+
+#ifndef AVALONIA_NATIVE_OSX_POPUPIMPL_H
+#define AVALONIA_NATIVE_OSX_POPUPIMPL_H
+
+#endif //AVALONIA_NATIVE_OSX_POPUPIMPL_H

native/Avalonia.Native/src/OSX/PopupImpl.mm

@@ -0,0 +1,61 @@
+//
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
+
+#include "WindowInterfaces.h"
+#include "AvnView.h"
+#include "WindowImpl.h"
+#include "automation.h"
+#include "menu.h"
+#include "common.h"
+#import "WindowBaseImpl.h"
+#import "WindowProtocol.h"
+#import <AppKit/AppKit.h>
+#include "PopupImpl.h"
+
+class PopupImpl : public virtual WindowBaseImpl, public IAvnPopup
+{
+private:
+    BEGIN_INTERFACE_MAP()
+    INHERIT_INTERFACE_MAP(WindowBaseImpl)
+    INTERFACE_MAP_ENTRY(IAvnPopup, IID_IAvnPopup)
+    END_INTERFACE_MAP()
+    virtual ~PopupImpl(){}
+    ComPtr<IAvnWindowEvents> WindowEvents;
+    PopupImpl(IAvnWindowEvents* events, IAvnGlContext* gl) : WindowBaseImpl(events, gl)
+    {
+        WindowEvents = events;
+    }
+protected:
+    virtual NSWindowStyleMask GetStyle() override
+    {
+        return NSWindowStyleMaskBorderless;
+    }
+    
+    virtual void OnInitialiseNSWindow () override
+    {
+        [Window setLevel:NSPopUpMenuWindowLevel];
+    }
+
+public:
+    virtual bool ShouldTakeFocusOnShow() override
+    {
+        return false;
+    }
+
+    virtual HRESULT Show(bool activate, bool isDialog) override
+    {
+        return WindowBaseImpl::Show(activate, true);
+    }
+};
+
+
+extern IAvnPopup* CreateAvnPopup(IAvnWindowEvents*events, IAvnGlContext* gl)
+{
+    @autoreleasepool
+    {
+        IAvnPopup* ptr = dynamic_cast<IAvnPopup*>(new PopupImpl(events, gl));
+        return ptr;
+    }
+}

native/Avalonia.Native/src/OSX/ResizeScope.h

@@ -6,7 +6,6 @@
 #ifndef AVALONIA_NATIVE_OSX_RESIZESCOPE_H
 #define AVALONIA_NATIVE_OSX_RESIZESCOPE_H
 
-#include "window.h"
 #include "avalonia-native.h"
 
 @class AvnView;

native/Avalonia.Native/src/OSX/ResizeScope.mm

@@ -5,7 +5,7 @@
 
 #import <AppKit/AppKit.h>
 #include "ResizeScope.h"
-#import "AvnView.h"
+#include "AvnView.h"
 
 ResizeScope::ResizeScope(AvnView *view, AvnPlatformResizeReason reason) {
     _view = view;

native/Avalonia.Native/src/OSX/SystemDialogs.mm

@@ -1,5 +1,4 @@
 #include "common.h"
-#include "window.h"
 #include "INSWindowHolder.h"
 
 class SystemDialogs : public ComSingleObject<IAvnSystemDialogs, &IID_IAvnSystemDialogs>

native/Avalonia.Native/src/OSX/WindowBaseImpl.h

@@ -6,16 +6,16 @@
 #ifndef AVALONIA_NATIVE_OSX_WINDOWBASEIMPL_H
 #define AVALONIA_NATIVE_OSX_WINDOWBASEIMPL_H
 
-#import "rendertarget.h"
+#include "rendertarget.h"
 #include "INSWindowHolder.h"
 
 @class AutoFitContentView;
+@class AvnMenu;
+@protocol AvnWindowProtocol;
 
 class WindowBaseImpl : public virtual ComObject,
                        public virtual IAvnWindowBase,
                        public INSWindowHolder {
-private:
-    NSCursor *cursor;
 
 public:
     FORWARD_IUNKNOWN()
@@ -24,22 +24,7 @@ BEGIN_INTERFACE_MAP()
         INTERFACE_MAP_ENTRY(IAvnWindowBase, IID_IAvnWindowBase)
     END_INTERFACE_MAP()
 
-    virtual ~WindowBaseImpl() {
+    virtual ~WindowBaseImpl();
-        View = NULL;
-        Window = NULL;
-    }
-
-    AutoFitContentView *StandardContainer;
-    AvnView *View;
-    AvnWindow *Window;
-    ComPtr<IAvnWindowBaseEvents> BaseEvents;
-    ComPtr<IAvnGlContext> _glContext;
-    NSObject <IRenderTarget> *renderTarget;
-    AvnPoint lastPositionSet;
-    NSString *_lastTitle;
-
-    bool _shown;
-    bool _inResize;
 
     WindowBaseImpl(IAvnWindowBaseEvents *events, IAvnGlContext *gl);
 
@@ -51,12 +36,14 @@ BEGIN_INTERFACE_MAP()
 
     virtual HRESULT ObtainNSViewHandleRetained(void **ret) override;
 
-    virtual AvnWindow *GetNSWindow() override;
+    virtual NSWindow *GetNSWindow() override;
 
-    virtual AvnView *GetNSView() override;
+    virtual NSView *GetNSView() override;
 
     virtual HRESULT Show(bool activate, bool isDialog) override;
 
+    virtual bool IsShown ();
+
     virtual bool ShouldTakeFocusOnShow();
 
     virtual HRESULT Hide() override;
@@ -111,11 +98,39 @@ BEGIN_INTERFACE_MAP()
 
     virtual bool IsDialog();
 
+    id<AvnWindowProtocol> GetWindowProtocol ();
+
 protected:
     virtual NSWindowStyleMask GetStyle();
 
     void UpdateStyle();
+                           
+    virtual void OnInitialiseNSWindow ();
 
+private:
+    void CreateNSWindow (bool isDialog);
+    void CleanNSWindow ();
+    void InitialiseNSWindow ();
+
+    NSCursor *cursor;
+    ComPtr<IAvnGlContext> _glContext;
+    bool hasPosition;
+    NSSize lastSize;
+    NSSize lastMinSize;
+    NSSize lastMaxSize;
+    AvnMenu* lastMenu;
+    bool _inResize;
+
+protected:
+    AvnPoint lastPositionSet;
+    AutoFitContentView *StandardContainer;
+    bool _shown;
+
+public:
+    NSObject <IRenderTarget> *renderTarget;
+    NSWindow * Window;
+    ComPtr<IAvnWindowBaseEvents> BaseEvents;
+    AvnView *View;
 };
 
 #endif //AVALONIA_NATIVE_OSX_WINDOWBASEIMPL_H

native/Avalonia.Native/src/OSX/WindowBaseImpl.mm

@@ -5,13 +5,21 @@
 
 #import <AppKit/AppKit.h>
 #include "common.h"
-#import "window.h"
+#include "AvnView.h"
-#import "AvnView.h"
 #include "menu.h"
 #include "automation.h"
-#import "cursor.h"
+#include "cursor.h"
 #include "ResizeScope.h"
-#import "AutoFitContentView.h"
+#include "AutoFitContentView.h"
+#import "WindowProtocol.h"
+#import "WindowInterfaces.h"
+#include "WindowBaseImpl.h"
+
+
+WindowBaseImpl::~WindowBaseImpl() {
+    View = nullptr;
+    Window = nullptr;
+}
 
 WindowBaseImpl::WindowBaseImpl(IAvnWindowBaseEvents *events, IAvnGlContext *gl) {
     _shown = false;
@@ -22,17 +30,14 @@ WindowBaseImpl::WindowBaseImpl(IAvnWindowBaseEvents *events, IAvnGlContext *gl)
     View = [[AvnView alloc] initWithParent:this];
     StandardContainer = [[AutoFitContentView new] initWithContent:View];
 
-    Window = [[AvnWindow alloc] initWithParent:this];
+    lastPositionSet = { 0, 0 };
-    [Window setContentView:StandardContainer];
+    hasPosition = false;
-
+    lastSize = NSSize { 100, 100 };
-    lastPositionSet.X = 100;
+    lastMaxSize = NSSize { CGFLOAT_MAX, CGFLOAT_MAX};
-    lastPositionSet.Y = 100;
+    lastMinSize = NSSize { 0, 0 };
-    _lastTitle = @"";
 
-    [Window setStyleMask:NSWindowStyleMaskBorderless];
+    Window = nullptr;
-    [Window setBackingType:NSBackingStoreBuffered];
+    lastMenu = nullptr;
-
-    [Window setOpaque:false];
 }
 
 HRESULT WindowBaseImpl::ObtainNSViewHandle(void **ret) {
@@ -59,11 +64,11 @@ HRESULT WindowBaseImpl::ObtainNSViewHandleRetained(void **ret) {
     return S_OK;
 }
 
-AvnWindow *WindowBaseImpl::GetNSWindow() {
+NSWindow *WindowBaseImpl::GetNSWindow() {
     return Window;
 }
 
-AvnView *WindowBaseImpl::GetNSView() {
+NSView *WindowBaseImpl::GetNSView() {
     return View;
 }
 
@@ -83,10 +88,18 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
     START_COM_CALL;
 
     @autoreleasepool {
-        SetPosition(lastPositionSet);
+        CreateNSWindow(isDialog);
-        UpdateStyle();
+        InitialiseNSWindow();
+
+        if(hasPosition)
+        {
+            SetPosition(lastPositionSet);
+        } else
+        {
+            [Window center];
+        }
 
-        [Window setTitle:_lastTitle];
+        UpdateStyle();
 
         if (ShouldTakeFocusOnShow() && activate) {
             [Window orderFront:Window];
@@ -103,6 +116,11 @@ HRESULT WindowBaseImpl::Show(bool activate, bool isDialog) {
     }
 }
 
+bool WindowBaseImpl::IsShown ()
+{
+    return _shown;
+}
+
 bool WindowBaseImpl::ShouldTakeFocusOnShow() {
     return true;
 }
@@ -125,7 +143,8 @@ HRESULT WindowBaseImpl::Hide() {
     @autoreleasepool {
         if (Window != nullptr) {
             [Window orderOut:Window];
-            [Window restoreParentWindow];
+
+            [GetWindowProtocol() restoreParentWindow];
         }
 
         return S_OK;
@@ -181,9 +200,8 @@ HRESULT WindowBaseImpl::GetClientSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [View frame];
+        ret->Width = lastSize.width;
-        ret->Width = frame.size.width;
+        ret->Height = lastSize.height;
-        ret->Height = frame.size.height;
 
         return S_OK;
     }
@@ -196,9 +214,11 @@ HRESULT WindowBaseImpl::GetFrameSize(AvnSize *ret) {
         if (ret == nullptr)
             return E_POINTER;
 
-        auto frame = [Window frame];
+        if(Window != nullptr){
-        ret->Width = frame.size.width;
+            auto frame = [Window frame];
-        ret->Height = frame.size.height;
+            ret->Width = frame.size.width;
+            ret->Height = frame.size.height;
+        }
 
         return S_OK;
     }
@@ -225,8 +245,13 @@ HRESULT WindowBaseImpl::SetMinMaxSize(AvnSize minSize, AvnSize maxSize) {
     START_COM_CALL;
 
     @autoreleasepool {
-        [Window setContentMinSize:ToNSSize(minSize)];
+        lastMinSize = ToNSSize(minSize);
-        [Window setContentMaxSize:ToNSSize(maxSize)];
+        lastMaxSize = ToNSSize(maxSize);
+
+        if(Window != nullptr) {
+            [Window setContentMinSize:lastMinSize];
+            [Window setContentMaxSize:lastMaxSize];
+        }
 
         return S_OK;
     }
@@ -243,8 +268,8 @@ HRESULT WindowBaseImpl::Resize(double x, double y, AvnPlatformResizeReason reaso
     auto resizeBlock = ResizeScope(View, reason);
 
     @autoreleasepool {
-        auto maxSize = [Window contentMaxSize];
+        auto maxSize = lastMaxSize;
-        auto minSize = [Window contentMinSize];
+        auto minSize = lastMinSize;
 
         if (x < minSize.width) {
             x = minSize.width;
@@ -263,12 +288,15 @@ HRESULT WindowBaseImpl::Resize(double x, double y, AvnPlatformResizeReason reaso
         }
 
         @try {
+            lastSize = NSSize {x, y};
+
             if (!_shown) {
                 BaseEvents->Resized(AvnSize{x, y}, reason);
             }
 
-            [Window setContentSize:NSSize{x, y}];
+            if(Window != nullptr) {
-            [Window invalidateShadow];
+                [Window setContentSize:lastSize];
+            }
         }
         @finally {
             _inResize = false;
@@ -293,12 +321,14 @@ HRESULT WindowBaseImpl::SetMainMenu(IAvnMenu *menu) {
 
     auto nativeMenu = dynamic_cast<AvnAppMenu *>(menu);
 
-    auto nsmenu = nativeMenu->GetNative();
+    lastMenu = nativeMenu->GetNative();
 
-    [Window applyMenu:nsmenu];
+    if(Window != nullptr) {
+        [GetWindowProtocol() applyMenu:lastMenu];
 
-    if ([Window isKeyWindow]) {
+        if ([Window isKeyWindow]) {
-        [Window showWindowMenuWithAppMenu];
+            [GetWindowProtocol() showWindowMenuWithAppMenu];
+        }
     }
 
     return S_OK;
@@ -334,12 +364,17 @@ HRESULT WindowBaseImpl::GetPosition(AvnPoint *ret) {
             return E_POINTER;
         }
 
-        auto frame = [Window frame];
+        if(Window != nullptr) {
+            auto frame = [Window frame];
 
-        ret->X = frame.origin.x;
+            ret->X = frame.origin.x;
-        ret->Y = frame.origin.y + frame.size.height;
+            ret->Y = frame.origin.y + frame.size.height;
 
-        *ret = ConvertPointY(*ret);
+            *ret = ConvertPointY(*ret);
+        } else
+        {
+            *ret = lastPositionSet;
+        }
 
         return S_OK;
     }
@@ -350,7 +385,11 @@ HRESULT WindowBaseImpl::SetPosition(AvnPoint point) {
 
     @autoreleasepool {
         lastPositionSet = point;
-        [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+        hasPosition = true;
+
+        if(Window != nullptr) {
+            [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(point))];
+        }
 
         return S_OK;
     }
@@ -502,4 +541,75 @@ NSWindowStyleMask WindowBaseImpl::GetStyle() {
 
 void WindowBaseImpl::UpdateStyle() {
     [Window setStyleMask:GetStyle()];
-}
+}
+
+void WindowBaseImpl::CleanNSWindow() {
+    if(Window != nullptr) {
+        [GetWindowProtocol() disconnectParent];
+        [Window close];
+        Window = nullptr;
+    }
+}
+
+void WindowBaseImpl::CreateNSWindow(bool isDialog) {
+    if (isDialog) {
+        if (![Window isKindOfClass:[AvnPanel class]]) {
+            CleanNSWindow();
+
+            Window = [[AvnPanel alloc] initWithParent:this contentRect:NSRect{0, 0, lastSize} styleMask:GetStyle()];
+        }
+    } else {
+        if (![Window isKindOfClass:[AvnWindow class]]) {
+            CleanNSWindow();
+
+            Window = [[AvnWindow alloc] initWithParent:this contentRect:NSRect{0, 0, lastSize} styleMask:GetStyle()];
+        }
+    }
+}
+
+void WindowBaseImpl::OnInitialiseNSWindow()
+{
+    
+}
+
+void WindowBaseImpl::InitialiseNSWindow() {
+    if(Window != nullptr) {
+        [Window setContentView:StandardContainer];
+        [Window setStyleMask:NSWindowStyleMaskBorderless];
+        [Window setBackingType:NSBackingStoreBuffered];
+
+        [Window setContentSize:lastSize];
+        [Window setContentMinSize:lastMinSize];
+        [Window setContentMaxSize:lastMaxSize];
+
+        [Window setOpaque:false];
+
+        if (lastMenu != nullptr) {
+            [GetWindowProtocol() applyMenu:lastMenu];
+
+            if ([Window isKeyWindow]) {
+                [GetWindowProtocol() showWindowMenuWithAppMenu];
+            }
+        }
+        
+        OnInitialiseNSWindow();
+    }
+}
+
+id <AvnWindowProtocol> WindowBaseImpl::GetWindowProtocol() {
+    if(Window == nullptr)
+    {
+        return nullptr;
+    }
+
+    return (id <AvnWindowProtocol>) Window;
+}
+
+extern IAvnWindow* CreateAvnWindow(IAvnWindowEvents*events, IAvnGlContext* gl)
+{
+    @autoreleasepool
+    {
+        IAvnWindow* ptr = (IAvnWindow*)new WindowImpl(events, gl);
+        return ptr;
+    }
+}

native/Avalonia.Native/src/OSX/WindowImpl.h

@@ -6,7 +6,6 @@
 #ifndef AVALONIA_NATIVE_OSX_WINDOWIMPL_H
 #define AVALONIA_NATIVE_OSX_WINDOWIMPL_H
 
-
 #import "WindowBaseImpl.h"
 #include "IWindowStateChanged.h"
 
@@ -89,9 +88,14 @@ BEGIN_INTERFACE_MAP()
     virtual HRESULT SetWindowState (AvnWindowState state) override;
 
     virtual bool IsDialog() override;
+    
+    virtual void OnInitialiseNSWindow() override;
 
 protected:
     virtual NSWindowStyleMask GetStyle() override;
+
+private:
+    NSString *_lastTitle;
 };
 
 #endif //AVALONIA_NATIVE_OSX_WINDOWIMPL_H

native/Avalonia.Native/src/OSX/WindowImpl.mm

@@ -4,10 +4,10 @@
 //
 
 #import <AppKit/AppKit.h>
-#import "window.h"
+#include "AutoFitContentView.h"
-#import "AutoFitContentView.h"
+#include "AvnView.h"
-#import "AvnView.h"
 #include "automation.h"
+#include "WindowProtocol.h"
 
 WindowImpl::WindowImpl(IAvnWindowEvents *events, IAvnGlContext *gl) : WindowBaseImpl(events, gl) {
     _isClientAreaExtended = false;
@@ -19,11 +19,8 @@ WindowImpl::WindowImpl(IAvnWindowEvents *events, IAvnGlContext *gl) : WindowBase
     _inSetWindowState = false;
     _lastWindowState = Normal;
     _actualWindowState = Normal;
+    _lastTitle = @"";
     WindowEvents = events;
-    [Window setCanBecomeKeyAndMain];
-    [Window disableCursorRects];
-    [Window setTabbingMode:NSWindowTabbingModeDisallowed];
-    [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
 }
 
 void WindowImpl::HideOrShowTrafficLights() {
@@ -51,11 +48,27 @@ void WindowImpl::HideOrShowTrafficLights() {
     }
 }
 
+void WindowImpl::OnInitialiseNSWindow(){
+    [GetWindowProtocol() setCanBecomeKeyWindow:true];
+    [Window disableCursorRects];
+    [Window setTabbingMode:NSWindowTabbingModeDisallowed];
+    [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
+
+    [Window setTitle:_lastTitle];
+    
+    if(_isClientAreaExtended)
+    {
+        [GetWindowProtocol() setIsExtended:true];
+        SetExtendClientArea(true);
+    }
+}
+
 HRESULT WindowImpl::Show(bool activate, bool isDialog) {
     START_COM_CALL;
 
     @autoreleasepool {
         _isDialog = isDialog;
+
         WindowBaseImpl::Show(activate, isDialog);
 
         HideOrShowTrafficLights();
@@ -68,7 +81,7 @@ HRESULT WindowImpl::SetEnabled(bool enable) {
     START_COM_CALL;
 
     @autoreleasepool {
-        [Window setEnabled:enable];
+        [GetWindowProtocol() setEnabled:enable];
         return S_OK;
     }
 }
@@ -328,37 +341,39 @@ HRESULT WindowImpl::SetExtendClientArea(bool enable) {
     @autoreleasepool {
         _isClientAreaExtended = enable;
 
-        if (enable) {
+        if(Window != nullptr) {
-            Window.titleVisibility = NSWindowTitleHidden;
+            if (enable) {
+                Window.titleVisibility = NSWindowTitleHidden;
 
-            [Window setTitlebarAppearsTransparent:true];
+                [Window setTitlebarAppearsTransparent:true];
 
-            auto wantsTitleBar = (_extendClientHints & AvnSystemChrome) || (_extendClientHints & AvnPreferSystemChrome);
+                auto wantsTitleBar = (_extendClientHints & AvnSystemChrome) || (_extendClientHints & AvnPreferSystemChrome);
 
-            if (wantsTitleBar) {
+                if (wantsTitleBar) {
-                [StandardContainer ShowTitleBar:true];
+                    [StandardContainer ShowTitleBar:true];
-            } else {
+                } else {
-                [StandardContainer ShowTitleBar:false];
+                    [StandardContainer ShowTitleBar:false];
-            }
+                }
 
-            if (_extendClientHints & AvnOSXThickTitleBar) {
+                if (_extendClientHints & AvnOSXThickTitleBar) {
-                Window.toolbar = [NSToolbar new];
+                    Window.toolbar = [NSToolbar new];
-                Window.toolbar.showsBaselineSeparator = false;
+                    Window.toolbar.showsBaselineSeparator = false;
+                } else {
+                    Window.toolbar = nullptr;
+                }
             } else {
+                Window.titleVisibility = NSWindowTitleVisible;
                 Window.toolbar = nullptr;
+                [Window setTitlebarAppearsTransparent:false];
+                View.layer.zPosition = 0;
             }
-        } else {
-            Window.titleVisibility = NSWindowTitleVisible;
-            Window.toolbar = nullptr;
-            [Window setTitlebarAppearsTransparent:false];
-            View.layer.zPosition = 0;
-        }
 
-        [Window setIsExtended:enable];
+            [GetWindowProtocol() setIsExtended:enable];
 
-        HideOrShowTrafficLights();
+            HideOrShowTrafficLights();
 
-        UpdateStyle();
+            UpdateStyle();
+        }
 
         return S_OK;
     }
@@ -383,7 +398,7 @@ HRESULT WindowImpl::GetExtendTitleBarHeight(double *ret) {
             return E_POINTER;
         }
 
-        *ret = [Window getExtendedTitleBarHeight];
+        *ret = [GetWindowProtocol() getExtendedTitleBarHeight];
 
         return S_OK;
     }
@@ -417,6 +432,9 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
     START_COM_CALL;
 
     @autoreleasepool {
+        auto currentState = _actualWindowState;
+        _lastWindowState = state;
+
         if (Window == nullptr) {
             return S_OK;
         }
@@ -427,9 +445,6 @@ HRESULT WindowImpl::SetWindowState(AvnWindowState state) {
 
         _inSetWindowState = true;
 
-        auto currentState = _actualWindowState;
-        _lastWindowState = state;
-
         if (currentState == Normal) {
             _preZoomSize = [Window frame];
         }
@@ -508,7 +523,7 @@ bool WindowImpl::IsDialog() {
 }
 
 NSWindowStyleMask WindowImpl::GetStyle() {
-    unsigned long s = NSWindowStyleMaskBorderless;
+    unsigned long s = this->_isDialog ? NSWindowStyleMaskUtilityWindow : NSWindowStyleMaskBorderless;
 
     switch (_decorations) {
         case SystemDecorationsNone:

native/Avalonia.Native/src/OSX/WindowInterfaces.h

@@ -0,0 +1,17 @@
+//
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+#import <AppKit/AppKit.h>
+#include "WindowProtocol.h"
+#include "WindowBaseImpl.h"
+
+@interface AvnWindow : NSWindow <AvnWindowProtocol, NSWindowDelegate>
+-(AvnWindow* _Nonnull) initWithParent: (WindowBaseImpl* _Nonnull) parent contentRect: (NSRect)contentRect styleMask: (NSWindowStyleMask)styleMask;
+@end
+
+@interface AvnPanel : NSPanel <AvnWindowProtocol, NSWindowDelegate>
+-(AvnPanel* _Nonnull) initWithParent: (WindowBaseImpl* _Nonnull) parent contentRect: (NSRect)contentRect styleMask: (NSWindowStyleMask)styleMask;
+@end

native/Avalonia.Native/src/OSX/window.h → native/Avalonia.Native/src/OSX/WindowProtocol.h

@@ -1,15 +1,15 @@
-#ifndef window_h
+//
-#define window_h
+// Created by Dan Walmsley on 06/05/2022.
+// Copyright (c) 2022 Avalonia. All rights reserved.
+//
 
-#import "avalonia-native.h"
+#pragma once
 
-@class AvnMenu;
+#import <AppKit/AppKit.h>
 
-class WindowBaseImpl;
+@class AvnMenu;
 
-@interface AvnWindow : NSWindow <NSWindowDelegate>
+@protocol AvnWindowProtocol
--(AvnWindow* _Nonnull) initWithParent: (WindowBaseImpl* _Nonnull) parent;
--(void) setCanBecomeKeyAndMain;
 -(void) pollModalSession: (NSModalSession _Nonnull) session;
 -(void) restoreParentWindow;
 -(bool) shouldTryToHandleEvents;
@@ -20,7 +20,8 @@ class WindowBaseImpl;
 
 -(double) getExtendedTitleBarHeight;
 -(void) setIsExtended:(bool)value;
+-(void) disconnectParent;
 -(bool) isDialog;
-@end
 
-#endif /* window_h */
+-(void) setCanBecomeKeyWindow:(bool)value;
+@end

native/Avalonia.Native/src/OSX/automation.h

@@ -1,5 +1,6 @@
-#import <Cocoa/Cocoa.h>
+#pragma once
 
+#import <Cocoa/Cocoa.h>
 NS_ASSUME_NONNULL_BEGIN
 
 class IAvnAutomationPeer;

native/Avalonia.Native/src/OSX/automation.mm

@@ -1,9 +1,8 @@
 #include "common.h"
-#import "automation.h"
+#include "automation.h"
-#import "window.h"
 #include "AvnString.h"
-#import "INSWindowHolder.h"
+#include "INSWindowHolder.h"
-#import "AvnView.h"
+#include "AvnView.h"
 
 @interface AvnAccessibilityElement (Events)
 - (void) raiseChildrenChanged;

native/Avalonia.Native/src/OSX/main.mm

@@ -1,7 +1,6 @@
 //This file will contain actual IID structures
 #define COM_GUIDS_MATERIALIZE
 #include "common.h"
-#include "window.h"
 
 static NSString* s_appTitle = @"Avalonia";
 

native/Avalonia.Native/src/OSX/menu.mm

@@ -1,7 +1,6 @@
 
 #include "common.h"
 #include "menu.h"
-#import "window.h"
 #include "KeyTransform.h"
 #include <CoreFoundation/CoreFoundation.h>
 #include <Carbon/Carbon.h> /* For kVK_ constants, and TIS functions. */

samples/BindingDemo/BindingDemo.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
   </ItemGroup>

samples/ControlCatalog/ControlCatalog.csproj

@@ -25,6 +25,8 @@
     <ProjectReference Include="..\..\packages\Avalonia\Avalonia.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.ColorPicker\Avalonia.Controls.ColorPicker.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.DataGrid\Avalonia.Controls.DataGrid.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
     <ProjectReference Include="..\SampleControls\ControlSamples.csproj" />
   </ItemGroup>

samples/ControlCatalog/Pages/CalendarDatePickerPage.xaml

@@ -10,8 +10,7 @@
                 Margin="0,16,0,0"
                 HorizontalAlignment="Center"
                 Spacing="16">
-      <StackPanel Orientation="Vertical"
+      <StackPanel Orientation="Vertical">
-                  Width="200">
         <TextBlock Text="SelectedDateFormat: Short"/>
         <CalendarDatePicker Name="DatePicker1"
                     SelectedDateFormat="Short"

samples/ControlCatalog/Pages/TextBoxPage.xaml

@@ -66,6 +66,12 @@
                  FontFamily="Comic Sans MS"
                  InputMethod.IsInputMethodEnabled="False"
                  Foreground="Red"/>
+        <TextBox AcceptsReturn="True" 
+                 TextWrapping="Wrap" 
+                 Width="200" 
+                 Height="125"
+                 LineHeight="32"
+                 Text="Multiline TextBox with TextWrapping and increased LineHeight.&#xD;&#xD;Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est." />
       </StackPanel>
       <StackPanel Orientation="Vertical" Spacing="8" Margin="8">
         <Label Classes="h2" Target="{Binding #firstResMFont}">res_m fonts</Label>

samples/ControlCatalog/ViewModels/MainWindowViewModel.cs

@@ -18,7 +18,7 @@ namespace ControlCatalog.ViewModels
         private WindowState _windowState;
         private WindowState[] _windowStates;
         private int _transparencyLevel;
-        private ExtendClientAreaChromeHints _chromeHints;
+        private ExtendClientAreaChromeHints _chromeHints = ExtendClientAreaChromeHints.PreferSystemChrome;
         private bool _extendClientAreaEnabled;
         private bool _systemTitleBarEnabled;        
         private bool _preferSystemChromeEnabled;

samples/IntegrationTestApp/IntegrationTestApp.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
@@ -18,6 +18,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
   </ItemGroup>
   
   <Import Project="..\..\build\BuildTargets.targets" />

samples/PlatformSanityChecks/PlatformSanityChecks.csproj

@@ -7,6 +7,7 @@
 
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Desktop\Avalonia.Desktop.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.X11\Avalonia.X11.csproj" />
   </ItemGroup>
 

samples/Previewer/Previewer.csproj

@@ -9,6 +9,9 @@
     </Compile>
     <EmbeddedResource Include="**\*.xaml" />
   </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
+  </ItemGroup>
   
   <Import Project="..\..\build\SampleApp.props" />
   <Import Project="..\..\build\ReferenceCoreLibraries.props" />

samples/RenderDemo/RenderDemo.csproj

@@ -12,6 +12,7 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
     <ProjectReference Include="..\SampleControls\ControlSamples.csproj" />

samples/Sandbox/Sandbox.csproj

@@ -10,6 +10,7 @@
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.ColorPicker\Avalonia.Controls.ColorPicker.csproj" />
     <ProjectReference Include="..\..\src\Avalonia.Controls.DataGrid\Avalonia.Controls.DataGrid.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Fluent\Avalonia.Themes.Fluent.csproj" />
   </ItemGroup>
   
   <Import Project="..\..\build\SampleApp.props" />

samples/VirtualizationDemo/VirtualizationDemo.csproj

@@ -5,6 +5,7 @@
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
+    <ProjectReference Include="..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\src\Linux\Avalonia.LinuxFramebuffer\Avalonia.LinuxFramebuffer.csproj" />
     <ProjectReference Include="..\MiniMvvm\MiniMvvm.csproj" />
   </ItemGroup>

samples/interop/Direct3DInteropSample/Direct3DInteropSample.csproj

@@ -22,6 +22,7 @@
       </EmbeddedResource>
     </ItemGroup>
     <ItemGroup>
+        <ProjectReference Include="..\..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Direct2D1\Avalonia.Direct2D1.csproj" />
         <ProjectReference Include="..\..\..\src\Windows\Avalonia.Win32\Avalonia.Win32.csproj" />
         <ProjectReference Include="..\..\MiniMvvm\MiniMvvm.csproj" />

samples/interop/NativeEmbedSample/NativeEmbedSample.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="MonoMac.NetStandard" Version="0.0.4" />
+    <ProjectReference Include="..\..\..\src\Avalonia.Themes.Default\Avalonia.Themes.Default.csproj" />
     <ProjectReference Include="..\..\..\src\Windows\Avalonia.Direct2D1\Avalonia.Direct2D1.csproj" />
     <ProjectReference Include="..\..\..\src\Avalonia.Diagnostics\Avalonia.Diagnostics.csproj" />
     <ProjectReference Include="..\..\..\src\Avalonia.X11\Avalonia.X11.csproj" />

src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs

@@ -40,7 +40,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             _gl = GlPlatformSurface.TryCreate(this);
             _framebuffer = new FramebufferManager(this);
 
-            RenderScaling = (int)_view.Scaling;
+            RenderScaling = _view.Scaling;
 
             MaxClientSize = new PixelSize(_view.Resources.DisplayMetrics.WidthPixels,
                 _view.Resources.DisplayMetrics.HeightPixels).ToSize(RenderScaling);

src/Avalonia.Base/Animation/IAnimation.cs

@@ -1,12 +1,14 @@
 using System;
 using System.Threading;
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Animation objects
     /// </summary>
+    [NotClientImplementable]
     public interface IAnimation
     {
         /// <summary>

src/Avalonia.Base/Animation/IAnimationSetter.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IAnimationSetter
     {
         AvaloniaProperty? Property { get; set; }

src/Avalonia.Base/Animation/IAnimator.cs

@@ -1,11 +1,13 @@
 using System;
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Animator objects
     /// </summary>
+    [NotClientImplementable]
     public interface IAnimator : IList<AnimatorKeyFrame>
     {
         /// <summary>

src/Avalonia.Base/Animation/IClock.cs

@@ -1,9 +1,9 @@
 using System;
-using System.Collections.Generic;
+using Avalonia.Metadata;
-using System.Text;
 
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IClock : IObservable<TimeSpan>
     {
         PlayState PlayState { get; set; }

src/Avalonia.Base/Animation/IGlobalClock.cs

@@ -1,9 +1,8 @@
-using System;
+using Avalonia.Metadata;
-using System.Collections.Generic;
-using System.Text;
 
 namespace Avalonia.Animation
 {
+    [NotClientImplementable]
     public interface IGlobalClock : IClock
     {
     }

src/Avalonia.Base/Animation/ITransition.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Animation
 {
     /// <summary>
     /// Interface for Transition objects.
     /// </summary>
+    [NotClientImplementable]
     public interface ITransition
     {
         /// <summary>

src/Avalonia.Base/Collections/AvaloniaList.cs

@@ -394,7 +394,13 @@ namespace Avalonia.Collections
                         } while (en.MoveNext());
 
                         if (notificationItems is not null)
+                        {
                             NotifyAdd(notificationItems, index);
+                        }
+                        else
+                        {
+                            NotifyCountChanged();
+                        }
                     }
                 }
             }

src/Avalonia.Base/Controls/INameScope.cs

@@ -1,5 +1,4 @@
-using System;
+using Avalonia.Metadata;
-using System.Threading.Tasks;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls
@@ -7,6 +6,7 @@ namespace Avalonia.Controls
     /// <summary>
     /// Defines a name scope.
     /// </summary>
+    [NotClientImplementable]
     public interface INameScope
     {
         /// <summary>

src/Avalonia.Base/Controls/IPseudoClasses.cs

@@ -1,9 +1,11 @@
+using Avalonia.Metadata;
 
 namespace Avalonia.Controls
 {
     /// <summary>
     /// Exposes an interface for setting pseudoclasses on a <see cref="Classes"/> collection.
     /// </summary>
+    [NotClientImplementable]
     public interface IPseudoClasses
     {
         /// <summary>

src/Avalonia.Base/Controls/IResourceHost.cs

@@ -1,6 +1,5 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -10,6 +9,7 @@ namespace Avalonia.Controls
     /// <remarks>
     /// This interface is implemented by <see cref="StyledElement"/> and `Application`.
     /// </remarks>
+    [NotClientImplementable]
     public interface IResourceHost : IResourceNode
     {
         /// <summary>

src/Avalonia.Base/Controls/IResourceNode.cs

@@ -1,6 +1,5 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -12,6 +11,7 @@ namespace Avalonia.Controls
     /// (<see cref="IResourceHost"/>) and resource providers such as <see cref="ResourceDictionary"/>
     /// (see <see cref="IResourceProvider"/>).
     /// </remarks>
+    [NotClientImplementable]
     public interface IResourceNode
     {
         /// <summary>

src/Avalonia.Base/Controls/ISetInheritanceParent.cs

@@ -1,4 +1,4 @@
-#nullable enable
+using Avalonia.Metadata;
 
 namespace Avalonia.Controls
 {
@@ -10,6 +10,7 @@ namespace Avalonia.Controls
     /// Additionally, <see cref="ISetLogicalParent"/> also sets the inheritance parent; this
     /// interface is only needed where the logical and inheritance parents differ.
     /// </remarks>
+    [NotClientImplementable]
     public interface ISetInheritanceParent
     {
         /// <summary>

src/Avalonia.Base/Controls/ISetLogicalParent.cs

@@ -1,6 +1,5 @@
 using Avalonia.LogicalTree;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Controls
 {
@@ -10,6 +9,7 @@ namespace Avalonia.Controls
     /// <remarks>
     /// You should not usually need to use this interface - it is for advanced scenarios only.
     /// </remarks>
+    [NotClientImplementable]
     public interface ISetLogicalParent
     {
         /// <summary>

src/Avalonia.Base/Data/Core/ExpressionNode.cs

@@ -98,36 +98,36 @@ namespace Avalonia.Data.Core
 
         private void ValueChanged(object? value, bool notify)
         {
-            if (_subscriber is null)
+            if (_subscriber is { } subscriber)
-                return;
-
-            var notification = value as BindingNotification;
-
-            if (notification == null)
             {
-                LastValue = value != null ? new WeakReference<object?>(value) : NullReference;
+                var notification = value as BindingNotification;
+                var next = Next;
 
-                if (Next != null)
+                if (notification == null)
                 {
-                    Next.Target = LastValue;
+                    LastValue = value != null ? new WeakReference<object?>(value) : NullReference;
+                    if (next != null)
+                    {
+                        next.Target = LastValue;
+                    }
+                    else if (notify)
+                    {
+                        subscriber(value);
+                    }
                 }
-                else if (notify)
+                else
                 {
-                    _subscriber(value);
+                    LastValue = notification.Value != null ? new WeakReference<object?>(notification.Value) : NullReference;
-                }
-            }
-            else
-            {
-                LastValue = notification.Value != null ? new WeakReference<object?>(notification.Value) : NullReference;
 
-                if (Next != null)
+                    if (next != null)
-                {
+                    {
-                    Next.Target = LastValue;
+                        next.Target = LastValue;
-                }
+                    }
 
-                if (Next == null || notification.Error != null)
+                    if (next == null || notification.Error != null)
-                {
+                    {
-                    _subscriber(value);
+                        subscriber(value);
+                    }
                 }
             }
         }

src/Avalonia.Base/Data/Core/IPropertyInfo.cs

@@ -1,7 +1,9 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Data.Core
 {
+    [NotClientImplementable]
     public interface IPropertyInfo
     {
         string Name { get; }

src/Avalonia.Base/Data/Core/Plugins/InpcPropertyAccessorPlugin.cs

@@ -17,7 +17,7 @@ namespace Avalonia.Data.Core.Plugins
             new Dictionary<(Type, string), PropertyInfo?>();
 
         /// <inheritdoc/>
-        public bool Match(object obj, string propertyName) => GetFirstPropertyWithName(obj.GetType(), propertyName) != null;
+        public bool Match(object obj, string propertyName) => GetFirstPropertyWithName(obj, propertyName) != null;
 
         /// <summary>
         /// Starts monitoring the value of a property on an object.
@@ -36,7 +36,7 @@ namespace Avalonia.Data.Core.Plugins
             if (!reference.TryGetTarget(out var instance) || instance is null)
                 return null;
 
-            var p = GetFirstPropertyWithName(instance.GetType(), propertyName);
+            var p = GetFirstPropertyWithName(instance, propertyName);
 
             if (p != null)
             {
@@ -50,8 +50,16 @@ namespace Avalonia.Data.Core.Plugins
             }
         }
 
-        private PropertyInfo? GetFirstPropertyWithName(Type type, string propertyName)
+        private const BindingFlags PropertyBindingFlags =
+            BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance;
+        
+        private PropertyInfo? GetFirstPropertyWithName(object instance, string propertyName)
         {
+            if (instance is IReflectableType reflectableType)
+                return reflectableType.GetTypeInfo().GetProperty(propertyName, PropertyBindingFlags);
+
+            var type = instance.GetType();
+            
             var key = (type, propertyName);
 
             if (!_propertyLookup.TryGetValue(key, out var propertyInfo))
@@ -66,10 +74,7 @@ namespace Avalonia.Data.Core.Plugins
         {
             PropertyInfo? found = null;
 
-            const BindingFlags bindingFlags =
+            var properties = type.GetProperties(PropertyBindingFlags);
-                BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static | BindingFlags.Instance;
-
-            var properties = type.GetProperties(bindingFlags);
 
             foreach (PropertyInfo propertyInfo in properties)
             {

src/Avalonia.Base/Data/IBinding.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Data
 {
     /// <summary>
     /// Holds a binding that can be applied to a property on an object.
     /// </summary>
+    [NotClientImplementable]
     public interface IBinding
     {
         /// <summary>

src/Avalonia.Base/DirectPropertyBase.cs

@@ -2,7 +2,6 @@
 using Avalonia.Data;
 using Avalonia.Reactive;
 using Avalonia.Styling;
-using Avalonia.Utilities;
 
 namespace Avalonia
 {
@@ -188,10 +187,10 @@ namespace Avalonia
             }
             else if (value is ITemplate template && !typeof(ITemplate).IsAssignableFrom(PropertyType))
             {
-                return new PropertySetterLazyInstance<TValue>(
+                return new PropertySetterTemplateInstance<TValue>(
                     target,
                     this,
-                    () => (TValue)template.Build());
+                    template);
             }
             else
             {

src/Avalonia.Base/IAvaloniaObject.cs

@@ -1,11 +1,13 @@
 using System;
 using Avalonia.Data;
+using Avalonia.Metadata;
 
 namespace Avalonia
 {
     /// <summary>
     /// Interface for getting/setting <see cref="AvaloniaProperty"/> values on an object.
     /// </summary>
+    [NotClientImplementable]
     public interface IAvaloniaObject
     {
         /// <summary>

src/Avalonia.Base/IDataContextProvider.cs

@@ -1,10 +1,11 @@
-#nullable enable
+using Avalonia.Metadata;
 
 namespace Avalonia
 {
     /// <summary>
     /// Defines an element with a data context that can be used for binding.
     /// </summary>
+    [NotClientImplementable]
     public interface IDataContextProvider : IAvaloniaObject
     {
         /// <summary>

src/Avalonia.Base/IDirectPropertyAccessor.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia
 {

src/Avalonia.Base/IDirectPropertyMetadata.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia
 {
     /// <summary>
     /// Untyped interface to <see cref="DirectPropertyMetadata{TValue}"/>
     /// </summary>
+    [NotClientImplementable]
     public interface IDirectPropertyMetadata
     {
         /// <summary>

src/Avalonia.Base/IStyledElement.cs

@@ -2,12 +2,12 @@
 using System.ComponentModel;
 using Avalonia.Controls;
 using Avalonia.LogicalTree;
+using Avalonia.Metadata;
 using Avalonia.Styling;
 
-#nullable enable
-
 namespace Avalonia
 {
+    [NotClientImplementable]
     public interface IStyledElement :
         IStyleable,
         IStyleHost,

src/Avalonia.Base/IStyledPropertyMetadata.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia
 {
     /// <summary>
     /// Untyped interface to <see cref="StyledPropertyMetadata{TValue}"/>
     /// </summary>
+    [NotClientImplementable]
     public interface IStyledPropertyMetadata
     {
         /// <summary>

src/Avalonia.Base/Input/IAccessKeyHandler.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for classes that handle access keys for a window.
     /// </summary>
+    [Unstable]
     public interface IAccessKeyHandler
     {
         /// <summary>

src/Avalonia.Base/Input/IFocusManager.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Manages focus for the application.
     /// </summary>
+    [NotClientImplementable]
     public interface IFocusManager
     {
         /// <summary>

src/Avalonia.Base/Input/IInputDevice.cs

@@ -1,7 +1,9 @@
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IInputDevice
     {
         /// <summary>

src/Avalonia.Base/Input/IInputElement.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 #nullable enable
@@ -10,6 +11,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Defines input-related functionality for a control.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputElement : IInteractive, IVisual
     {
         /// <summary>

src/Avalonia.Base/Input/IInputManager.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
@@ -7,6 +8,7 @@ namespace Avalonia.Input
     /// Receives input from the windowing subsystem and dispatches it to interested parties
     /// for processing.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputManager
     {
         /// <summary>

src/Avalonia.Base/Input/IInputRoot.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for top-level input elements.
     /// </summary>
+    [NotClientImplementable]
     public interface IInputRoot : IInputElement
     {
         /// <summary>

src/Avalonia.Base/Input/IKeyboardDevice.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
@@ -50,6 +51,7 @@ namespace Avalonia.Input
         KeyboardMask = Alt | Control | Shift | Meta
     }
 
+    [NotClientImplementable]
     public interface IKeyboardDevice : IInputDevice, INotifyPropertyChanged
     {
         IInputElement? FocusedElement { get; }

src/Avalonia.Base/Input/IKeyboardNavigationHandler.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input
 {
     /// <summary>
     /// Defines the interface for classes that handle keyboard navigation for a window.
     /// </summary>
+    [Unstable]
     public interface IKeyboardNavigationHandler
     {
         /// <summary>

src/Avalonia.Base/Input/IMainMenu.cs

@@ -1,5 +1,6 @@
 using System;
 using Avalonia.Interactivity;
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Input
@@ -7,6 +8,7 @@ namespace Avalonia.Input
     /// <summary>
     /// Defines the interface for a window's main menu.
     /// </summary>
+    [NotClientImplementable]
     public interface IMainMenu : IVisual
     {
         /// <summary>

src/Avalonia.Base/Input/IMouseDevice.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
     /// <summary>
     /// Represents a mouse device.
     /// </summary>
+    [NotClientImplementable]
     public interface IMouseDevice : IPointerDevice
     {
         /// <summary>

src/Avalonia.Base/Input/IPointer.cs

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

src/Avalonia.Base/Input/IPointerDevice.cs

@@ -1,9 +1,11 @@
 using System;
 using Avalonia.VisualTree;
 using Avalonia.Input.Raw;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input
 {
+    [NotClientImplementable]
     public interface IPointerDevice : IInputDevice
     {
         /// <inheritdoc cref="IPointer.Captured" />

src/Avalonia.Base/Input/InputElement.cs

@@ -94,7 +94,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<KeyEventArgs> KeyDownEvent =
             RoutedEvent.Register<InputElement, KeyEventArgs>(
-                "KeyDown",
+                nameof(KeyDown),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -102,7 +102,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<KeyEventArgs> KeyUpEvent =
             RoutedEvent.Register<InputElement, KeyEventArgs>(
-                "KeyUp",
+                nameof(KeyUp),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -116,7 +116,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<TextInputEventArgs> TextInputEvent =
             RoutedEvent.Register<InputElement, TextInputEventArgs>(
-                "TextInput",
+                nameof(TextInput),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
         
         /// <summary>
@@ -124,7 +124,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<TextInputMethodClientRequestedEventArgs> TextInputMethodClientRequestedEvent =
             RoutedEvent.Register<InputElement, TextInputMethodClientRequestedEventArgs>(
-                "TextInputMethodClientRequested",
+                nameof(TextInputMethodClientRequested),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -144,7 +144,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerEventArgs> PointerMovedEvent =
             RoutedEvent.Register<InputElement, PointerEventArgs>(
-                "PointerMove",
+                nameof(PointerMoved),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -152,7 +152,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerPressedEventArgs> PointerPressedEvent =
             RoutedEvent.Register<InputElement, PointerPressedEventArgs>(
-                "PointerPressed",
+                nameof(PointerPressed),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>
@@ -160,7 +160,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerReleasedEventArgs> PointerReleasedEvent =
             RoutedEvent.Register<InputElement, PointerReleasedEventArgs>(
-                "PointerReleased",
+                nameof(PointerReleased),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
         
         /// <summary>
@@ -168,7 +168,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerCaptureLostEventArgs> PointerCaptureLostEvent =
             RoutedEvent.Register<InputElement, PointerCaptureLostEventArgs>(
-                "PointerCaptureLost", 
+                nameof(PointerCaptureLost), 
                 RoutingStrategies.Direct);
 
         /// <summary>
@@ -176,7 +176,7 @@ namespace Avalonia.Input
         /// </summary>
         public static readonly RoutedEvent<PointerWheelEventArgs> PointerWheelChangedEvent =
             RoutedEvent.Register<InputElement, PointerWheelEventArgs>(
-                "PointerWheelChanged",
+                nameof(PointerWheelChanged),
                 RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
 
         /// <summary>

src/Avalonia.Base/Input/Platform/IClipboard.cs

@@ -1,7 +1,9 @@
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input.Platform
 {
+    [NotClientImplementable]
     public interface IClipboard
     {
         Task<string> GetTextAsync();

src/Avalonia.Base/Input/Platform/IPlatformDragSource.cs

@@ -1,7 +1,9 @@
 using System.Threading.Tasks;
+using Avalonia.Metadata;
 
 namespace Avalonia.Input.Platform
 {
+    [Unstable]
     public interface IPlatformDragSource
     {
         Task<DragDropEffects> DoDragDrop(PointerEventArgs triggerEvent, IDataObject data, DragDropEffects allowedEffects);

src/Avalonia.Base/Input/Raw/IDragDropDevice.cs

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

src/Avalonia.Base/Input/TextInput/ITextInputMethodImpl.cs

@@ -1,5 +1,8 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Input.TextInput
 {
+    [Unstable]
     public interface ITextInputMethodImpl
     {
         void SetClient(ITextInputMethodClient? client);
@@ -8,6 +11,7 @@ namespace Avalonia.Input.TextInput
         void Reset();
     }
     
+    [NotClientImplementable]
     public interface ITextInputMethodRoot : IInputRoot
     {
         ITextInputMethodImpl? InputMethod { get; }

src/Avalonia.Base/Interactivity/IInteractive.cs

@@ -1,4 +1,5 @@
 using System;
+using Avalonia.Metadata;
 
 #nullable enable
 
@@ -7,6 +8,7 @@ namespace Avalonia.Interactivity
     /// <summary>
     /// Interface for objects that raise routed events.
     /// </summary>
+    [NotClientImplementable]
     public interface IInteractive
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutManager.cs

@@ -1,12 +1,12 @@
 using System;
-
+using Avalonia.Metadata;
-#nullable enable
 
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Manages measuring and arranging of controls.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutManager : IDisposable
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutRoot.cs

@@ -1,8 +1,11 @@
+using Avalonia.Metadata;
+
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Defines the root of a layoutable tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutRoot : ILayoutable
     {
         /// <summary>

src/Avalonia.Base/Layout/ILayoutable.cs

@@ -1,12 +1,12 @@
+using Avalonia.Metadata;
 using Avalonia.VisualTree;
 
-#nullable enable
-
 namespace Avalonia.Layout
 {
     /// <summary>
     /// Defines layout-related functionality for a control.
     /// </summary>
+    [NotClientImplementable]
     public interface ILayoutable : IVisual
     {
         /// <summary>

src/Avalonia.Base/Layout/Layoutable.cs

@@ -141,7 +141,6 @@ namespace Avalonia.Layout
         static Layoutable()
         {
             AffectsMeasure<Layoutable>(
-                IsVisibleProperty,
                 WidthProperty,
                 HeightProperty,
                 MinWidthProperty,
@@ -791,6 +790,25 @@ namespace Avalonia.Layout
         {
         }
 
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == IsVisibleProperty)
+            {
+                DesiredSize = default;
+
+                // All changes to visibility cause the parent element to be notified.
+                this.GetVisualParent<ILayoutable>()?.ChildDesiredSizeChanged(this);
+
+                // We only invalidate outselves when visibility is changed to true.
+                if (change.GetNewValue<bool>())
+                {
+                    InvalidateMeasure();
+                }
+            }
+        }
+
         /// <inheritdoc/>
         protected sealed override void OnVisualParentChanged(IVisual? oldParent, IVisual? newParent)
         {

src/Avalonia.Base/Layout/UniformGridLayout.cs

@@ -116,7 +116,7 @@ namespace Avalonia.Layout
         /// Defines the <see cref="MaximumRowsOrColumnsProperty"/> property.
         /// </summary>
         public static readonly StyledProperty<int> MaximumRowsOrColumnsProperty =
-            AvaloniaProperty.Register<UniformGridLayout, int>(nameof(MinItemWidth));
+            AvaloniaProperty.Register<UniformGridLayout, int>(nameof(MaximumRowsOrColumns));
 
         /// <summary>
         /// Defines the <see cref="Orientation"/> property.

src/Avalonia.Base/LogicalTree/ILogical.cs

@@ -1,12 +1,14 @@
 using System;
 using Avalonia.Collections;
 using Avalonia.Controls;
+using Avalonia.Metadata;
 
 namespace Avalonia.LogicalTree
 {
     /// <summary>
     /// Represents a node in the logical tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILogical
     {
         /// <summary>

src/Avalonia.Base/LogicalTree/ILogicalRoot.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.LogicalTree
+using Avalonia.Metadata;
+
+namespace Avalonia.LogicalTree
 {
     /// <summary>
     /// Represents a root of a logical tree.
     /// </summary>
+    [NotClientImplementable]
     public interface ILogicalRoot : ILogical
     {
     }

src/Avalonia.Base/Media/ConicGradientBrush.cs

@@ -11,7 +11,7 @@ namespace Avalonia.Media
         /// Defines the <see cref="Center"/> property.
         /// </summary>
         public static readonly StyledProperty<RelativePoint> CenterProperty =
-            AvaloniaProperty.Register<RadialGradientBrush, RelativePoint>(
+            AvaloniaProperty.Register<ConicGradientBrush, RelativePoint>(
                 nameof(Center),
                 RelativePoint.Center);
 
@@ -19,7 +19,7 @@ namespace Avalonia.Media
         /// Defines the <see cref="Angle"/> property.
         /// </summary>
         public static readonly StyledProperty<double> AngleProperty =
-            AvaloniaProperty.Register<RadialGradientBrush, double>(
+            AvaloniaProperty.Register<ConicGradientBrush, double>(
                 nameof(Angle),
                 0);
         

src/Avalonia.Base/Media/IBrush.cs

@@ -1,4 +1,5 @@
 using System.ComponentModel;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
@@ -6,6 +7,7 @@ namespace Avalonia.Media
     /// Describes how an area is painted.
     /// </summary>
     [TypeConverter(typeof(BrushConverter))]
+    [NotClientImplementable]
     public interface IBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IConicGradientBrush.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with a conic gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IConicGradientBrush : IGradientBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IDashStyle.cs

@@ -1,10 +1,12 @@
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Represents the sequence of dashes and gaps that will be applied by a <see cref="Pen"/>.
     /// </summary>
+    [NotClientImplementable]
     public interface IDashStyle
     {
         /// <summary>

src/Avalonia.Base/Media/IExperimentalAcrylicMaterial.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Experimental Interface for producing Acrylic-like materials.
     /// </summary>
+    [NotClientImplementable]
     public interface IExperimentalAcrylicMaterial
     {
         /// <summary>

src/Avalonia.Base/Media/IGradientBrush.cs

@@ -1,10 +1,12 @@
 using System.Collections.Generic;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// A brush that draws with a gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IGradientBrush : IBrush
     {
         /// <summary>

src/Avalonia.Base/Media/IGradientStop.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Describes the location and color of a transition point in a gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface IGradientStop
     {
         /// <summary>

src/Avalonia.Base/Media/IImageBrush.cs

@@ -1,10 +1,12 @@
 using Avalonia.Media.Imaging;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Paints an area with an <see cref="IBitmap"/>.
     /// </summary>
+    [NotClientImplementable]
     public interface IImageBrush : ITileBrush
     {
         /// <summary>
@@ -12,4 +14,4 @@ namespace Avalonia.Media
         /// </summary>
         IBitmap Source { get; }
     }
-}
+}

src/Avalonia.Base/Media/ILinearGradientBrush.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// A brush that draws with a linear gradient.
     /// </summary>
+    [NotClientImplementable]
     public interface ILinearGradientBrush : IGradientBrush
     {
         /// <summary>
@@ -15,4 +18,4 @@
         /// </summary>
         RelativePoint EndPoint { get; }
     }
-}
+}

src/Avalonia.Base/Media/IMutableBrush.cs

@@ -1,10 +1,12 @@
 using System;
+using Avalonia.Metadata;
 
 namespace Avalonia.Media
 {
     /// <summary>
     /// Represents a mutable brush which can return an immutable clone of itself.
     /// </summary>
+    [NotClientImplementable]
     public interface IMutableBrush : IBrush, IAffectsRender
     {
         /// <summary>

src/Avalonia.Base/Media/IMutableExperimentalAcrylicMaterial.cs

@@ -1,8 +1,11 @@
-namespace Avalonia.Media
+using Avalonia.Metadata;
+
+namespace Avalonia.Media
 {
     /// <summary>
     /// Represents a mutable brush which can return an immutable clone of itself.
     /// </summary>
+    [NotClientImplementable]
     public interface IMutableExperimentalAcrylicMaterial : IExperimentalAcrylicMaterial, IAffectsRender
     {
         /// <summary>