Merge branch 'master' into feature/ui-automation

.gitignore

@@ -106,6 +106,9 @@ _NCrunch_*/
 *.ncrunchsolution.user
 nCrunchTemp_*
 
+# CodeRush
+.cr/
+
 # Others
 sql/
 *.Cache

Avalonia.sln.DotSettings

@@ -1,5 +1,4 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
-	<s:Boolean x:Key="/Default/CodeInspection/ExcludedFiles/FileMasksToSkip/=_002A_002Examl/@EntryIndexedValue">True</s:Boolean>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=3E53A01A_002DB331_002D47F3_002DB828_002D4A5717E77A24_002Fd_003Aglass/@EntryIndexedValue">ExplicitlyExcluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=6417B24E_002D49C2_002D4985_002D8DB2_002D3AB9D898EC91/@EntryIndexedValue">ExplicitlyExcluded</s:String>
 	<s:String x:Key="/Default/CodeInspection/ExcludedFiles/FilesAndFoldersToSkip2/=E3A1060B_002D50D0_002D44E8_002D88B6_002DF44EF2E5BD72_002Ff_003Ahtml_002Ehtm/@EntryIndexedValue">ExplicitlyExcluded</s:String>
@@ -39,4 +38,4 @@
 	<s:String x:Key="/Default/CodeStyle/Naming/CSharpNaming/PredefinedNamingRules/=TypesAndNamespaces/@EntryIndexedValue">&lt;Policy Inspect="False" Prefix="" Suffix="" Style="AaBb" /&gt;</s:String>
 	<s:Boolean x:Key="/Default/Environment/SettingsMigration/IsMigratorApplied/=JetBrains_002EReSharper_002EFeature_002EServices_002EDaemon_002ESettings_002EMigration_002ESwaWarningsModeSettingsMigrate/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Avalonia/@EntryIndexedValue">True</s:Boolean>
-	<s:Boolean x:Key="/Default/UserDictionary/Words/=Fcitx/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Fcitx/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

azure-pipelines.yml

@@ -1,7 +1,7 @@
 jobs:
 - job: Linux
   pool:
-    vmImage: 'ubuntu-16.04'
+    vmImage: 'ubuntu-20.04'
   steps:
   - task: CmdLine@2
     displayName: 'Install Nuke'

build/MicroCom.targets

@@ -15,7 +15,8 @@
           Inputs="@(AvnComIdl);$(MSBuildThisFileDirectory)../src/tools/MicroComGenerator/**/*.cs"
           Outputs="%(AvnComIdl.OutputFile)">
     <Message Importance="high" Text="Generating file %(AvnComIdl.OutputFile) from @(AvnComIdl)" />
-    <Exec Command="dotnet $(MSBuildThisFileDirectory)../src/tools/MicroComGenerator/bin/$(Configuration)/netcoreapp3.1/MicroComGenerator.dll -i @(AvnComIdl) --cs %(AvnComIdl.OutputFile)" LogStandardErrorAsError="true" />
+    <Exec Command="dotnet &quot;$(MSBuildThisFileDirectory)../src/tools/MicroComGenerator/bin/$(Configuration)/netcoreapp3.1/MicroComGenerator.dll&quot; -i @(AvnComIdl) --cs %(AvnComIdl.OutputFile)" 
+          LogStandardErrorAsError="true" />
     <ItemGroup>
       <!-- Remove and re-add generated file, this is needed for the clean build -->
       <Compile Remove="%(AvnComIdl.OutputFile)"/>

native/Avalonia.Native/inc/comimpl.h

@@ -8,8 +8,109 @@
 
 #include <cstring>
 
+/**
+ START_COM_CALL causes AddRef to be called at the beggining of a function.
+ When a function is exited, it causes ReleaseRef to be called.
+ This ensures that the object cannot be destroyed whilst the function is running.
+ For example: Window Show is called, which triggers an event, and user calls Close inside the event
+ causing the refcount to reach 0, and the object to be destroyed. Function then continues and this pointer
+ will now be invalid.
+ 
+ START_COM_CALL protects against this scenario.
+ */
+#define START_COM_CALL auto r = this->UnknownSelf()
+
 __IID_DEF(IUnknown, 0, 0, 0, C0, 00, 00, 00, 00, 00, 00, 46);
 
+template<class TInterface>
+class ComPtr
+{
+private:
+    TInterface* _obj;
+public:
+    ComPtr()
+    {
+        _obj = 0;
+    }
+    
+    ComPtr(TInterface* pObj)
+    {
+        _obj = 0;
+
+        if (pObj)
+        {
+            _obj = pObj;
+            _obj->AddRef();
+        }
+    }
+    
+    ComPtr(const ComPtr& ptr)
+    {
+        _obj = 0;
+        
+        if (ptr._obj)
+        {
+            _obj = ptr._obj;
+            _obj->AddRef();
+        }
+
+    }
+    
+    ComPtr& operator=(ComPtr other)
+    {
+        if(_obj != NULL)
+            _obj->Release();
+        _obj = other._obj;
+        if(_obj != NULL)
+            _obj->AddRef();
+        return *this;
+    }
+
+    ~ComPtr()
+    {
+        if (_obj)
+        {
+            _obj->Release();
+            _obj = 0;
+        }
+    }
+    
+    TInterface* getRaw()
+    {
+        return _obj;
+    }
+    
+    TInterface* getRetainedReference()
+    {
+        if(_obj == NULL)
+            return NULL;
+        _obj->AddRef();
+        return _obj;
+    }
+    
+    TInterface** getPPV()
+    {
+        return &_obj;
+    }
+    
+    operator TInterface*() const
+    {
+        return _obj;
+    }
+    TInterface& operator*() const
+    {
+        return *_obj;
+    }
+    TInterface** operator&()
+    {
+        return &_obj;
+    }
+    TInterface* operator->() const
+    {
+        return _obj;
+    }
+};
+
 class ComObject : public virtual IUnknown
 {
 private:
@@ -58,6 +159,12 @@ public:
         _refCount++;
         return S_OK;
     }
+    
+protected:
+   ComPtr<IUnknown> UnknownSelf()
+    {
+       return this;
+   }
 
 };
 
@@ -104,94 +211,5 @@ public:
     virtual ~ComSingleObject(){}
 };
 
-template<class TInterface>
-class ComPtr
-{
-private:
-    TInterface* _obj;
-public:
-    ComPtr()
-    {
-        _obj = 0;
-    }
-    
-    ComPtr(TInterface* pObj)
-    {
-        _obj = 0;
-
-        if (pObj)
-        {
-            _obj = pObj;
-            _obj->AddRef();
-        }
-    }
-    
-    ComPtr(const ComPtr& ptr)
-    {
-        _obj = 0;
-        
-        if (ptr._obj)
-        {
-            _obj = ptr._obj;
-            _obj->AddRef();
-        }
-
-    }
-    
-    ComPtr& operator=(ComPtr other)
-    {
-        if(_obj != NULL)
-            _obj->Release();
-        _obj = other._obj;
-        if(_obj != NULL)
-            _obj->AddRef();
-        return *this;
-    }
-
-    ~ComPtr()
-    {
-        if (_obj)
-        {
-            _obj->Release();
-            _obj = 0;
-        }
-    }
-    
-    TInterface* getRaw()
-    {
-        return _obj;
-    }
-    
-    TInterface* getRetainedReference()
-    {
-        if(_obj == NULL)
-            return NULL;
-        _obj->AddRef();
-        return _obj;
-    }
-    
-    TInterface** getPPV()
-    {
-        return &_obj;
-    }
-    
-    operator TInterface*() const
-    {
-        return _obj;
-    }
-    TInterface& operator*() const
-    {
-        return *_obj;
-    }
-    TInterface** operator&()
-    {
-        return &_obj;
-    }
-    TInterface* operator->() const
-    {
-        return _obj;
-    }
-};
-
 #endif // COMIMPL_H_INCLUDED
 #pragma clang diagnostic pop

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

@@ -43,6 +43,8 @@ public:
     
     virtual HRESULT Pointer(void**retOut) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(retOut == nullptr)
@@ -58,14 +60,19 @@ public:
     
     virtual HRESULT Length(int*retOut) override
     {
-        if(retOut == nullptr)
+        START_COM_CALL;
+        
+        @autoreleasepool
         {
-            return E_POINTER;
+            if(retOut == nullptr)
+            {
+                return E_POINTER;
+            }
+            
+            *retOut = _length;
+            
+            return S_OK;
         }
-        
-        *retOut = _length;
-        
-        return S_OK;
     }
 };
 
@@ -109,10 +116,15 @@ public:
     
     virtual HRESULT Get(unsigned int index, IAvnString**ppv) override
     {
-        if(_list.size() <= index)
+        START_COM_CALL;
-            return E_INVALIDARG;
+        
-        *ppv = _list[index].getRetainedReference();
+        @autoreleasepool
-        return S_OK;
+        {
+            if(_list.size() <= index)
+                return E_INVALIDARG;
+            *ppv = _list[index].getRetainedReference();
+            return S_OK;
+        }
     }
 };
 

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

@@ -222,6 +222,7 @@ std::map<int, const char*> s_QwertyKeyMap =
     { 45, "n" },
     { 46, "m" },
     { 47, "." },
+    { 48, "\t" },
     { 49, " " },
     { 50, "`" },
     { 51, "" },

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

@@ -8,6 +8,8 @@ class Screens : public ComSingleObject<IAvnScreens, &IID_IAvnScreens>
 public:
     virtual HRESULT GetScreenCount (int* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             *ret = (int)[NSScreen screens].count;
@@ -18,6 +20,8 @@ public:
     
     virtual HRESULT GetScreen (int index, AvnScreen* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(index < 0 || index >= [NSScreen screens].count)

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

@@ -50,6 +50,12 @@ ComPtr<IAvnApplicationEvents> _events;
     
     _events->FilesOpened(array);
 }
+
+- (NSApplicationTerminateReply)applicationShouldTerminate:(NSApplication *)sender
+{
+    return _events->TryShutdown() ? NSTerminateNow : NSTerminateCancel;
+}
+
 @end
 
 @interface AvnApplication : NSApplication

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

@@ -69,6 +69,8 @@ public:
     
     virtual HRESULT LegacyMakeCurrent() override
     {
+        START_COM_CALL;
+        
         if(CGLSetCurrentContext(Context) != 0)
             return E_FAIL;
         return S_OK;
@@ -76,6 +78,8 @@ public:
     
     virtual HRESULT MakeCurrent(IUnknown** ppv) override
     {
+        START_COM_CALL;
+        
         CGLContextObj saved = CGLGetCurrentContext();
         CGLLockContext(Context);
         if(CGLSetCurrentContext(Context) != 0)
@@ -128,6 +132,8 @@ public:
     
     virtual HRESULT CreateContext(IAvnGlContext* share, IAvnGlContext**ppv) override
     {
+        START_COM_CALL;
+        
         CGLContextObj shareContext = nil;
         if(share != nil)
         {
@@ -144,6 +150,8 @@ public:
     
     virtual HRESULT WrapContext(void* native, IAvnGlContext**ppv) override
     {
+        START_COM_CALL;
+        
         if(native == nil)
             return E_INVALIDARG;
         *ppv = new AvnGlContext((CGLContextObj) native);

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

@@ -25,6 +25,8 @@ public:
    
     virtual HRESULT GetText (char* type, IAvnString**ppv) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ppv == nullptr)
@@ -42,6 +44,8 @@ public:
     
     virtual HRESULT GetStrings(char* type, IAvnStringArray**ppv) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             *ppv= nil;
@@ -69,56 +73,71 @@ public:
     
     virtual HRESULT SetText (char* type, char* utf8String) override
     {
-        Clear();
+        START_COM_CALL;
+        
         @autoreleasepool
         {
+            Clear();
+            
             auto string = [NSString stringWithUTF8String:(const char*)utf8String];
             auto typeString = [NSString stringWithUTF8String:(const char*)type];
             if(_item == nil)
                 [_pb setString: string forType: typeString];
             else
                 [_item setString: string forType:typeString];
-        }
         
-        return S_OK;
+            return S_OK;
+        }
     }
     
     virtual HRESULT SetBytes(char* type, void* bytes, int len) override
     {
-        auto typeString = [NSString stringWithUTF8String:(const char*)type];
+        START_COM_CALL;
-        auto data = [NSData dataWithBytes:bytes length:len];
+        
-        if(_item == nil)
+        @autoreleasepool
-            [_pb setData:data forType:typeString];
+        {
-        else
+            auto typeString = [NSString stringWithUTF8String:(const char*)type];
-            [_item setData:data forType:typeString];
+            auto data = [NSData dataWithBytes:bytes length:len];
-        return S_OK;
+            if(_item == nil)
+                [_pb setData:data forType:typeString];
+            else
+                [_item setData:data forType:typeString];
+            return S_OK;
+        }
     }
        
     virtual HRESULT GetBytes(char* type, IAvnString**ppv) override
     {
-        *ppv = nil;
+        START_COM_CALL;
-        auto typeString = [NSString stringWithUTF8String:(const char*)type];
+        
-        NSData*data;
+        @autoreleasepool
-        @try
         {
-            if(_item)
+            *ppv = nil;
-                data = [_item dataForType:typeString];
+            auto typeString = [NSString stringWithUTF8String:(const char*)type];
-            else
+            NSData*data;
-                data = [_pb dataForType:typeString];
+            @try
-            if(data == nil)
+            {
+                if(_item)
+                    data = [_item dataForType:typeString];
+                else
+                    data = [_pb dataForType:typeString];
+                if(data == nil)
+                    return E_FAIL;
+            }
+            @catch(NSException* e)
+            {
                 return E_FAIL;
+            }
+            *ppv = CreateByteArray((void*)data.bytes, (int)data.length);
+            return S_OK;
         }
-        @catch(NSException* e)
-        {
-            return E_FAIL;
-        }
-        *ppv = CreateByteArray((void*)data.bytes, (int)data.length);
-        return S_OK;
     }
 
 
     virtual HRESULT Clear() override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(_item != nil)
@@ -128,15 +147,20 @@ public:
                 [_pb clearContents];
                 [_pb setString:@"" forType:NSPasteboardTypeString];
             }
-        }
         
-        return S_OK;
+            return S_OK;
+        }
     }
     
     virtual HRESULT ObtainFormats(IAvnStringArray** ppv) override
     {
-        *ppv = CreateAvnStringArray(_item == nil ? [_pb types] : [_item types]);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = CreateAvnStringArray(_item == nil ? [_pb types] : [_item types]);
+            return S_OK;
+        }
     }
 };
 

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

@@ -16,11 +16,16 @@ public:
     
     virtual HRESULT CreateDefaultChild(void* parent, void** retOut) override
     {
-        NSView* view = [NSView new];
+        START_COM_CALL;
-        [view setWantsLayer: true];
         
-        *retOut = (__bridge_retained void*)view;
+        @autoreleasepool
-        return S_OK;
+        {
+            NSView* view = [NSView new];
+            [view setWantsLayer: true];
+            
+            *retOut = (__bridge_retained void*)view;
+            return S_OK;
+        }
     };
     
     virtual IAvnNativeControlHostTopLevelAttachment* CreateAttachment() override
@@ -69,32 +74,42 @@ public:
     
     virtual HRESULT InitializeWithChildHandle(void* child) override
     {
-        if(_child != nil)
+        START_COM_CALL;
-            return E_FAIL;
+        
-        _child = (__bridge NSView*)child;
+        @autoreleasepool
-        if(_child == nil)
+        {
-            return E_FAIL;
+            if(_child != nil)
-        [_holder addSubview:_child];
+                return E_FAIL;
-        [_child setHidden: false];
+            _child = (__bridge NSView*)child;
-        return S_OK;
+            if(_child == nil)
+                return E_FAIL;
+            [_holder addSubview:_child];
+            [_child setHidden: false];
+            return S_OK;
+        }
     };
     
     virtual HRESULT AttachTo(IAvnNativeControlHost* host) override
     {
-        if(host == nil)
+        START_COM_CALL;
-        {
+        
-            [_holder removeFromSuperview];
+        @autoreleasepool
-            [_holder setHidden: true];
-        }
-        else
         {
-            AvnNativeControlHost* chost = dynamic_cast<AvnNativeControlHost*>(host);
+            if(host == nil)
-            if(chost == nil || chost->View == nil)
+            {
-                return E_FAIL;
+                [_holder removeFromSuperview];
-            [_holder setHidden:true];
+                [_holder setHidden: true];
-            [chost->View addSubview:_holder];
+            }
+            else
+            {
+                AvnNativeControlHost* chost = dynamic_cast<AvnNativeControlHost*>(host);
+                if(chost == nil || chost->View == nil)
+                    return E_FAIL;
+                [_holder setHidden:true];
+                [chost->View addSubview:_holder];
+            }
+            return S_OK;
         }
-        return S_OK;
     };
     
     virtual void ShowInBounds(float x, float y, float width, float height) override

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

@@ -53,36 +53,46 @@ public:
     
     virtual HRESULT GetCursor (AvnStandardCursorType cursorType, IAvnCursor** retOut) override
     {
-        *retOut = s_cursorMap[cursorType];
+        START_COM_CALL;
         
-        if(*retOut != nullptr)
+        @autoreleasepool
         {
-            (*retOut)->AddRef();
+            *retOut = s_cursorMap[cursorType];
-        }
             
-        return S_OK;
+            if(*retOut != nullptr)
+            {
+                (*retOut)->AddRef();
+            }
+                
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateCustomCursor (void* bitmapData, size_t length, AvnPixelSize hotPixel, IAvnCursor** retOut) override
     {
-        if(bitmapData == nullptr || retOut == nullptr)
+        START_COM_CALL;
+        
+        @autoreleasepool
         {
-            return E_POINTER;
+            if(bitmapData == nullptr || retOut == nullptr)
+            {
+                return E_POINTER;
+            }
+            
+            NSData *imageData = [NSData dataWithBytes:bitmapData length:length];
+            NSImage *image = [[NSImage alloc] initWithData:imageData];
+            
+            
+            NSPoint hotSpot;
+            hotSpot.x = hotPixel.Width;
+            hotSpot.y = hotPixel.Height;
+            
+            *retOut = new Cursor([[NSCursor new] initWithImage: image hotSpot: hotSpot]);
+            
+            (*retOut)->AddRef();
+            
+            return S_OK;
         }
-        
-        NSData *imageData = [NSData dataWithBytes:bitmapData length:length];
-        NSImage *image = [[NSImage alloc] initWithData:imageData];
-        
-        
-        NSPoint hotSpot;
-        hotSpot.x = hotPixel.Width;
-        hotSpot.y = hotPixel.Height;
-        
-        *retOut = new Cursor([[NSCursor new] initWithImage: image hotSpot: hotSpot]);
-        
-        (*retOut)->AddRef();
-        
-        return S_OK;
     }
 };
 

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

@@ -108,27 +108,42 @@ public:
     
     virtual HRESULT SetApplicationTitle(char* utf8String) override
     {
-        auto appTitle = [NSString stringWithUTF8String: utf8String];
+        START_COM_CALL;
         
-        [[NSProcessInfo processInfo] setProcessName:appTitle];
+        @autoreleasepool
-        
+        {
-        
+            auto appTitle = [NSString stringWithUTF8String: utf8String];
-        SetProcessName(appTitle);
+            
-        
+            [[NSProcessInfo processInfo] setProcessName:appTitle];
-        return S_OK;
+            
+            
+            SetProcessName(appTitle);
+            
+            return S_OK;
+        }
     }
     
     virtual HRESULT SetShowInDock(int show)  override
     {
-        AvnDesiredActivationPolicy = show
+        START_COM_CALL;
-            ? NSApplicationActivationPolicyRegular : NSApplicationActivationPolicyAccessory;
+        
-        return S_OK;
+        @autoreleasepool
+        {
+            AvnDesiredActivationPolicy = show
+                ? NSApplicationActivationPolicyRegular : NSApplicationActivationPolicyAccessory;
+            return S_OK;
+        }
     }
     
     virtual HRESULT SetDisableDefaultApplicationMenuItems (bool enabled) override
     {
-        SetAutoGenerateDefaultAppMenuItems(!enabled);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            SetAutoGenerateDefaultAppMenuItems(!enabled);
+            return S_OK;
+        }
     }
 };
 
@@ -166,6 +181,8 @@ public:
     FORWARD_IUNKNOWN()
     virtual HRESULT Initialize(IAvnGCHandleDeallocatorCallback* deallocator, IAvnApplicationEvents* events) override
     {
+        START_COM_CALL;
+        
         _deallocator = deallocator;
         @autoreleasepool{
             [[ThreadingInitializer new] do];
@@ -181,83 +198,143 @@ public:
     
     virtual HRESULT CreateWindow(IAvnWindowEvents* cb, IAvnGlContext* gl, IAvnWindow** ppv)  override
     {
-        if(cb == nullptr || ppv == nullptr)
+        START_COM_CALL;
-            return E_POINTER;
+        
-        *ppv = CreateAvnWindow(cb, gl);
+        @autoreleasepool
-        return S_OK;
+        {
+            if(cb == nullptr || ppv == nullptr)
+                return E_POINTER;
+            *ppv = CreateAvnWindow(cb, gl);
+            return S_OK;
+        }
     };
     
     virtual HRESULT CreatePopup(IAvnWindowEvents* cb, IAvnGlContext* gl, IAvnPopup** ppv) override
     {
-        if(cb == nullptr || ppv == nullptr)
+        START_COM_CALL;
-            return E_POINTER;
         
-        *ppv = CreateAvnPopup(cb, gl);
+        @autoreleasepool
-        return S_OK;
+        {
+            if(cb == nullptr || ppv == nullptr)
+                return E_POINTER;
+            
+            *ppv = CreateAvnPopup(cb, gl);
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreatePlatformThreadingInterface(IAvnPlatformThreadingInterface** ppv)  override
     {
-        *ppv = CreatePlatformThreading();
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = CreatePlatformThreading();
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateSystemDialogs(IAvnSystemDialogs** ppv) override
     {
-        *ppv = ::CreateSystemDialogs();
+        START_COM_CALL;
-        return  S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateSystemDialogs();
+            return  S_OK;
+        }
     }
     
     virtual HRESULT CreateScreens (IAvnScreens** ppv) override
     {
-        *ppv = ::CreateScreens ();
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateScreens ();
+            return S_OK;
+        }
     }
 
     virtual HRESULT CreateClipboard(IAvnClipboard** ppv) override
     {
-        *ppv = ::CreateClipboard (nil, nil);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateClipboard (nil, nil);
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateDndClipboard(IAvnClipboard** ppv) override
     {
-        *ppv = ::CreateClipboard (nil, [NSPasteboardItem new]);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateClipboard (nil, [NSPasteboardItem new]);
+            return S_OK;
+        }
     }
 
     virtual HRESULT CreateCursorFactory(IAvnCursorFactory** ppv) override
     {
-        *ppv = ::CreateCursorFactory();
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateCursorFactory();
+            return S_OK;
+        }
     }
     
     virtual HRESULT ObtainGlDisplay(IAvnGlDisplay** ppv) override
     {
-        auto rv = ::GetGlDisplay();
+        START_COM_CALL;
-        if(rv == NULL)
+        
-            return E_FAIL;
+        @autoreleasepool
-        rv->AddRef();
+        {
-        *ppv = rv;
+            auto rv = ::GetGlDisplay();
-        return S_OK;
+            if(rv == NULL)
+                return E_FAIL;
+            rv->AddRef();
+            *ppv = rv;
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateMenu (IAvnMenuEvents* cb, IAvnMenu** ppv) override
     {
-        *ppv = ::CreateAppMenu(cb);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateAppMenu(cb);
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateMenuItem (IAvnMenuItem** ppv) override
     {
-        *ppv = ::CreateAppMenuItem();
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateAppMenuItem();
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateMenuItemSeparator (IAvnMenuItem** ppv) override
     {
-        *ppv = ::CreateAppMenuItemSeparator();
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            *ppv = ::CreateAppMenuItemSeparator();
+            return S_OK;
+        }
     }
     
     virtual HRESULT CreateAutomationNode (IAvnAutomationPeer* peer, IAvnAutomationNode** ppv) override
@@ -268,8 +345,13 @@ public:
     
     virtual HRESULT SetAppMenu (IAvnMenu* appMenu) override
     {
-        ::SetAppMenu(s_appTitle, appMenu);
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            ::SetAppMenu(s_appTitle, appMenu);
+            return S_OK;
+        }
     }
 };
 

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

@@ -95,6 +95,8 @@ NSMenuItem* AvnAppMenuItem::GetNative()
 
 HRESULT AvnAppMenuItem::SetSubMenu (IAvnMenu* menu)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if(menu != nullptr)
@@ -114,6 +116,8 @@ HRESULT AvnAppMenuItem::SetSubMenu (IAvnMenu* menu)
 
 HRESULT AvnAppMenuItem::SetTitle (char* utf8String)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if (utf8String != nullptr)
@@ -128,6 +132,8 @@ HRESULT AvnAppMenuItem::SetTitle (char* utf8String)
 
 HRESULT AvnAppMenuItem::SetGesture (AvnKey key, AvnInputModifiers modifiers)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if(key != AvnKeyNone)
@@ -183,6 +189,8 @@ HRESULT AvnAppMenuItem::SetGesture (AvnKey key, AvnInputModifiers modifiers)
 
 HRESULT AvnAppMenuItem::SetAction (IAvnPredicateCallback* predicate, IAvnActionCallback* callback)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         _predicate = predicate;
@@ -193,6 +201,8 @@ HRESULT AvnAppMenuItem::SetAction (IAvnPredicateCallback* predicate, IAvnActionC
 
 HRESULT AvnAppMenuItem::SetIsChecked (bool isChecked)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         [_native setState:(isChecked && _isCheckable ? NSOnState : NSOffState)];
@@ -202,6 +212,8 @@ HRESULT AvnAppMenuItem::SetIsChecked (bool isChecked)
 
 HRESULT AvnAppMenuItem::SetToggleType(AvnMenuItemToggleType toggleType)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         switch(toggleType)
@@ -231,6 +243,8 @@ HRESULT AvnAppMenuItem::SetToggleType(AvnMenuItemToggleType toggleType)
 
 HRESULT AvnAppMenuItem::SetIcon(void *data, size_t length)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if(data != nullptr)
@@ -317,6 +331,8 @@ void AvnAppMenu::RaiseClosed()
 
 HRESULT AvnAppMenu::InsertItem(int index, IAvnMenuItem *item)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if([_native hasGlobalMenuItem])
@@ -337,6 +353,8 @@ HRESULT AvnAppMenu::InsertItem(int index, IAvnMenuItem *item)
 
 HRESULT AvnAppMenu::RemoveItem (IAvnMenuItem* item)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         auto avnMenuItem = dynamic_cast<AvnAppMenuItem*>(item);
@@ -352,6 +370,8 @@ HRESULT AvnAppMenu::RemoveItem (IAvnMenuItem* item)
 
 HRESULT AvnAppMenu::SetTitle (char* utf8String)
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         if (utf8String != nullptr)
@@ -365,6 +385,8 @@ HRESULT AvnAppMenu::SetTitle (char* utf8String)
 
 HRESULT AvnAppMenu::Clear()
 {
+    START_COM_CALL;
+    
     @autoreleasepool
     {
         [_native removeAllItems];

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

@@ -114,6 +114,8 @@ public:
     
     virtual HRESULT RunLoop(IAvnLoopCancellation* cancel) override
     {
+        START_COM_CALL;
+        
         auto can = dynamic_cast<LoopCancellation*>(cancel);
         if(can->Cancelled)
             return S_OK;

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

@@ -247,6 +247,8 @@ public:
     
     virtual HRESULT GetPixelSize(AvnPixelSize* ret)  override
     {
+        START_COM_CALL;
+        
         if(!_surface)
             return E_FAIL;
         *ret = _surface->size;
@@ -255,6 +257,8 @@ public:
     
     virtual HRESULT GetScaling(double* ret)  override
     {
+        START_COM_CALL;
+        
         if(!_surface)
             return E_FAIL;
         *ret = _surface->scale;
@@ -281,6 +285,8 @@ public:
     
     virtual HRESULT BeginDrawing(IAvnGlSurfaceRenderingSession** ret)  override
     {
+        START_COM_CALL;
+        
         ComPtr<IUnknown> releaseContext;
         @synchronized (_target->lock) {
             if(_target->surface == nil)

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

@@ -10,6 +10,8 @@ class WindowBaseImpl;
 -(void) setSwRenderedFrame: (AvnFramebuffer* _Nonnull) fb dispose: (IUnknown* _Nonnull) dispose;
 -(void) onClosed;
 -(AvnPixelSize) getPixelSize;
+-(AvnPlatformResizeReason) getResizeReason;
+-(void) setResizeReason:(AvnPlatformResizeReason)reason;
 @end
 
 @interface AutoFitContentView : NSView
@@ -34,6 +36,7 @@ class WindowBaseImpl;
 -(double) getScaling;
 -(double) getExtendedTitleBarHeight;
 -(void) setIsExtended:(bool)value;
+-(bool) isDialog;
 @end
 
 struct INSWindowHolder
@@ -51,4 +54,23 @@ struct IWindowStateChanged
     virtual AvnWindowState WindowState () = 0;
 };
 
+class ResizeScope
+{
+public:
+    ResizeScope(AvnView* _Nonnull view, AvnPlatformResizeReason reason)
+    {
+        _view = view;
+        _restore = [view getResizeReason];
+        [view setResizeReason:reason];
+    }
+    
+    ~ResizeScope()
+    {
+        [_view setResizeReason:_restore];
+    }
+private:
+    AvnView* _Nonnull _view;
+    AvnPlatformResizeReason _restore;
+};
+
 #endif /* window_h */

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

@@ -40,10 +40,12 @@ public:
     IAvnMenu* _mainMenu;
     
     bool _shown;
+    bool _inResize;
     
     WindowBaseImpl(IAvnWindowBaseEvents* events, IAvnGlContext* gl)
     {
         _shown = false;
+        _inResize = false;
         _mainMenu = nullptr;
         BaseEvents = events;
         _glContext = gl;
@@ -61,10 +63,13 @@ public:
         [Window setBackingType:NSBackingStoreBuffered];
         
         [Window setOpaque:false];
+        [Window setContentView: StandardContainer];
     }
     
     virtual HRESULT ObtainNSWindowHandle(void** ret) override
     {
+        START_COM_CALL;
+        
         if (ret == nullptr)
         {
             return E_POINTER;
@@ -77,6 +82,8 @@ public:
     
     virtual HRESULT ObtainNSWindowHandleRetained(void** ret) override
     {
+        START_COM_CALL;
+        
         if (ret == nullptr)
         {
             return E_POINTER;
@@ -89,6 +96,8 @@ public:
     
     virtual HRESULT ObtainNSViewHandle(void** ret) override
     {
+        START_COM_CALL;
+        
         if (ret == nullptr)
         {
             return E_POINTER;
@@ -101,6 +110,8 @@ public:
     
     virtual HRESULT ObtainNSViewHandleRetained(void** ret) override
     {
+        START_COM_CALL;
+        
         if (ret == nullptr)
         {
             return E_POINTER;
@@ -126,25 +137,28 @@ public:
         return Window;
     }
     
-    virtual HRESULT Show(bool activate) override
+    virtual HRESULT Show(bool activate, bool isDialog) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             SetPosition(lastPositionSet);
             UpdateStyle();
             
-            [Window setContentView: StandardContainer];
+            [Window setTitle:_lastTitle];
             
             if(ShouldTakeFocusOnShow() && activate)
             {
+                [Window orderFront: Window];
                 [Window makeKeyAndOrderFront:Window];
+                [Window makeFirstResponder:View];
                 [NSApp activateIgnoringOtherApps:YES];
             }
             else
             {
                 [Window orderFront: Window];
             }
-            [Window setTitle:_lastTitle];
             
             _shown = true;
             
@@ -159,6 +173,8 @@ public:
     
     virtual HRESULT Hide () override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(Window != nullptr)
@@ -173,6 +189,8 @@ public:
     
     virtual HRESULT Activate () override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(Window != nullptr)
@@ -187,6 +205,8 @@ public:
     
     virtual HRESULT SetTopMost (bool value) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             [Window setLevel: value ? NSFloatingWindowLevel : NSNormalWindowLevel];
@@ -197,11 +217,16 @@ public:
     
     virtual HRESULT Close() override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if (Window != nullptr)
             {
-                [Window close];
+                auto window = Window;
+                Window = nullptr;
+                
+                [window close];
             }
             
             return S_OK;
@@ -210,6 +235,8 @@ public:
     
     virtual HRESULT GetClientSize(AvnSize* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -223,8 +250,25 @@ public:
         }
     }
     
+    virtual HRESULT GetFrameSize(AvnSize* ret) override
+    {
+        @autoreleasepool
+        {
+            if(ret == nullptr)
+                return E_POINTER;
+            
+            auto frame = [Window frame];
+            ret->Width = frame.size.width;
+            ret->Height = frame.size.height;
+            
+            return S_OK;
+        }
+    }
+    
     virtual HRESULT GetScaling (double* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -243,6 +287,8 @@ public:
     
     virtual HRESULT SetMinMaxSize (AvnSize minSize, AvnSize maxSize) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             [Window setMinSize: ToNSSize(minSize)];
@@ -252,8 +298,18 @@ public:
         }
     }
     
-    virtual HRESULT Resize(double x, double y) override
+    virtual HRESULT Resize(double x, double y, AvnPlatformResizeReason reason) override
     {
+        if(_inResize)
+        {
+            return S_OK;
+        }
+        
+        _inResize = true;
+        
+        START_COM_CALL;
+        auto resizeBlock = ResizeScope(View, reason);
+        
         @autoreleasepool
         {
             auto maxSize = [Window maxSize];
@@ -279,13 +335,19 @@ public:
                 y = maxSize.height;
             }
             
-            if(!_shown)
+            @try
             {
-                BaseEvents->Resized(AvnSize{x,y});
+                if(!_shown)
+                {
+                    BaseEvents->Resized(AvnSize{x,y}, reason);
+                }
+                
+                [Window setContentSize:NSSize{x, y}];
+            }
+            @finally
+            {
+                _inResize = false;
             }
-            
-            [StandardContainer setFrameSize:NSSize{x,y}];
-            [Window setContentSize:NSSize{x, y}];
             
             return S_OK;
         }
@@ -293,6 +355,8 @@ public:
     
     virtual HRESULT Invalidate (AvnRect rect) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             [View setNeedsDisplayInRect:[View frame]];
@@ -303,6 +367,8 @@ public:
     
     virtual HRESULT SetMainMenu(IAvnMenu* menu) override
     {
+        START_COM_CALL;
+        
         _mainMenu = menu;
         
         auto nativeMenu = dynamic_cast<AvnAppMenu*>(menu);
@@ -321,6 +387,8 @@ public:
     
     virtual HRESULT BeginMoveDrag () override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             auto lastEvent = [View lastMouseDownEvent];
@@ -338,11 +406,15 @@ public:
     
     virtual HRESULT BeginResizeDrag (AvnWindowEdge edge) override
     {
+        START_COM_CALL;
+        
         return S_OK;
     }
     
     virtual HRESULT GetPosition (AvnPoint* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -363,6 +435,8 @@ public:
     
     virtual HRESULT SetPosition (AvnPoint point) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             lastPositionSet = point;
@@ -374,6 +448,8 @@ public:
     
     virtual HRESULT PointToClient (AvnPoint point, AvnPoint* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -392,6 +468,8 @@ public:
     
     virtual HRESULT PointToScreen (AvnPoint point, AvnPoint* ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -409,12 +487,16 @@ public:
     
     virtual HRESULT ThreadSafeSetSwRenderedFrame(AvnFramebuffer* fb, IUnknown* dispose) override
     {
+        START_COM_CALL;
+        
         [View setSwRenderedFrame: fb dispose: dispose];
         return S_OK;
     }
     
     virtual HRESULT SetCursor(IAvnCursor* cursor) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             Cursor* avnCursor = dynamic_cast<Cursor*>(cursor);
@@ -444,6 +526,8 @@ public:
     
     virtual HRESULT CreateGlRenderTarget(IAvnGlSurfaceRenderTarget** ppv) override
     {
+        START_COM_CALL;
+        
         if(View == NULL)
             return E_FAIL;
         *ppv = [renderTarget createSurfaceRenderTarget];
@@ -452,6 +536,8 @@ public:
     
     virtual HRESULT CreateNativeControlHost(IAvnNativeControlHost** retOut) override
     {
+        START_COM_CALL;
+        
         if(View == NULL)
             return E_FAIL;
         *retOut = ::CreateNativeControlHost(View);
@@ -460,6 +546,8 @@ public:
     
     virtual HRESULT SetBlurEnabled (bool enable) override
     {
+        START_COM_CALL;
+        
         [StandardContainer ShowBlur:enable];
         
         return S_OK;
@@ -469,6 +557,8 @@ public:
                                               IAvnClipboard* clipboard, IAvnDndResultCallback* cb,
                                               void* sourceHandle) override
     {
+        START_COM_CALL;
+        
         auto item = TryGetPasteboardItem(clipboard);
         [item setString:@"" forType:GetAvnCustomDataType()];
         if(item == nil)
@@ -528,6 +618,11 @@ public:
         }
     }
     
+    virtual bool IsDialog()
+    {
+        return false;
+    }
+    
 protected:
     virtual NSWindowStyleMask GetStyle()
     {
@@ -553,10 +648,12 @@ private:
     bool _fullScreenActive;
     SystemDecorations _decorations;
     AvnWindowState _lastWindowState;
+    AvnWindowState _actualWindowState;
     bool _inSetWindowState;
     NSRect _preZoomSize;
     bool _transitioningWindowState;
     bool _isClientAreaExtended;
+    bool _isDialog;
     AvnExtendClientAreaChromeHints _extendClientHints;
     
     FORWARD_IUNKNOWN()
@@ -579,14 +676,21 @@ private:
         _transitioningWindowState = false;
         _inSetWindowState = false;
         _lastWindowState = Normal;
+        _actualWindowState = Normal;
         WindowEvents = events;
         [Window setCanBecomeKeyAndMain];
         [Window disableCursorRects];
         [Window setTabbingMode:NSWindowTabbingModeDisallowed];
+        [Window setCollectionBehavior:NSWindowCollectionBehaviorFullScreenPrimary];
     }
     
     void HideOrShowTrafficLights ()
     {
+        if (Window == nil)
+        {
+            return;
+        }
+        
         for (id subview in Window.contentView.superview.subviews) {
             if ([subview isKindOfClass:NSClassFromString(@"NSTitlebarContainerView")]) {
                 NSView *titlebarView = [subview subviews][0];
@@ -611,11 +715,14 @@ private:
         }
     }
     
-    virtual HRESULT Show (bool activate) override
+    virtual HRESULT Show (bool activate, bool isDialog) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
-        {            
+        {
-            WindowBaseImpl::Show(activate);
+            _isDialog = isDialog;
+            WindowBaseImpl::Show(activate, isDialog);
             
             HideOrShowTrafficLights();
             
@@ -625,6 +732,8 @@ private:
     
     virtual HRESULT SetEnabled (bool enable) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             [Window setEnabled:enable];
@@ -634,6 +743,8 @@ private:
     
     virtual HRESULT SetParent (IAvnWindow* parent) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(parent == nullptr)
@@ -643,6 +754,12 @@ private:
             if(cparent == nullptr)
                 return E_INVALIDARG;
             
+            // If one tries to show a child window with a minimized parent window, then the parent window will be
+            // restored but MacOS isn't kind enough to *tell* us that, so the window will be left in a non-interactive
+            // state. Detect this and explicitly restore the parent window ourselves to avoid this situation.
+            if (cparent->WindowState() == Minimized)
+                cparent->SetWindowState(Normal);
+            
             [cparent->Window addChildWindow:Window ordered:NSWindowAbove];
             
             UpdateStyle();
@@ -673,7 +790,7 @@ private:
     
     void WindowStateChanged () override
     {
-        if(!_inSetWindowState && !_transitioningWindowState)
+        if(_shown && !_inSetWindowState && !_transitioningWindowState)
         {
             AvnWindowState state;
             GetWindowState(&state);
@@ -710,6 +827,7 @@ private:
                 }
                 
                 _lastWindowState = state;
+                _actualWindowState = state;
                 WindowEvents->WindowStateChanged(state);
             }
         }
@@ -745,6 +863,8 @@ private:
     
     virtual HRESULT SetCanResize(bool value) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             _canResize = value;
@@ -755,6 +875,8 @@ private:
     
     virtual HRESULT SetDecorations(SystemDecorations value) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             auto currentWindowState = _lastWindowState;
@@ -820,6 +942,8 @@ private:
     
     virtual HRESULT SetTitle (char* utf8title) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             _lastTitle = [NSString stringWithUTF8String:(const char*)utf8title];
@@ -831,6 +955,8 @@ private:
     
     virtual HRESULT SetTitleBarColor(AvnColor color) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             float a = (float)color.Alpha / 255.0f;
@@ -860,6 +986,8 @@ private:
     
     virtual HRESULT GetWindowState (AvnWindowState*ret) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if(ret == nullptr)
@@ -893,100 +1021,118 @@ private:
     
     virtual HRESULT TakeFocusFromChildren () override
     {
-        if(Window == nil)
+        START_COM_CALL;
-            return S_OK;
-        if([Window isKeyWindow])
-            [Window makeFirstResponder: View];
         
-        return S_OK;
+        @autoreleasepool
+        {
+            if(Window == nil)
+                return S_OK;
+            if([Window isKeyWindow])
+                [Window makeFirstResponder: View];
+            
+            return S_OK;
+        }
     }
     
     virtual HRESULT SetExtendClientArea (bool enable) override
     {
-        _isClientAreaExtended = enable;
+        START_COM_CALL;
         
-        if(enable)
+        @autoreleasepool
         {
-            Window.titleVisibility = NSWindowTitleHidden;
+            _isClientAreaExtended = enable;
-            
-            [Window setTitlebarAppearsTransparent:true];
             
-            auto wantsTitleBar = (_extendClientHints & AvnSystemChrome) || (_extendClientHints & AvnPreferSystemChrome);
+            if(enable)
-            
-            if (wantsTitleBar)
             {
-                [StandardContainer ShowTitleBar:true];
+                Window.titleVisibility = NSWindowTitleHidden;
-            }
+                
-            else
+                [Window setTitlebarAppearsTransparent:true];
-            {
+                
-                [StandardContainer ShowTitleBar:false];
+                auto wantsTitleBar = (_extendClientHints & AvnSystemChrome) || (_extendClientHints & AvnPreferSystemChrome);
-            }
+                
-            
+                if (wantsTitleBar)
-            if(_extendClientHints & AvnOSXThickTitleBar)
+                {
-            {
+                    [StandardContainer ShowTitleBar:true];
-                Window.toolbar = [NSToolbar new];
+                }
-                Window.toolbar.showsBaselineSeparator = false;
+                else
+                {
+                    [StandardContainer ShowTitleBar:false];
+                }
+                
+                if(_extendClientHints & AvnOSXThickTitleBar)
+                {
+                    Window.toolbar = [NSToolbar new];
+                    Window.toolbar.showsBaselineSeparator = false;
+                }
+                else
+                {
+                    Window.toolbar = nullptr;
+                }
             }
             else
             {
+                Window.titleVisibility = NSWindowTitleVisible;
                 Window.toolbar = nullptr;
+                [Window setTitlebarAppearsTransparent:false];
+                View.layer.zPosition = 0;
             }
+            
+            [Window setIsExtended:enable];
+            
+            HideOrShowTrafficLights();
+            
+            UpdateStyle();
+            
+            return S_OK;
         }
-        else
-        {
-            Window.titleVisibility = NSWindowTitleVisible;
-            Window.toolbar = nullptr;
-            [Window setTitlebarAppearsTransparent:false];
-            View.layer.zPosition = 0;
-        }
-        
-        [Window setIsExtended:enable];
-        
-        HideOrShowTrafficLights();
-        
-        UpdateStyle();
-        
-        return S_OK;
     }
     
     virtual HRESULT SetExtendClientAreaHints (AvnExtendClientAreaChromeHints hints) override
     {
-        _extendClientHints = hints;
+        START_COM_CALL;
         
-        SetExtendClientArea(_isClientAreaExtended);
+        @autoreleasepool
-        return S_OK;
+        {
+            _extendClientHints = hints;
+            
+            SetExtendClientArea(_isClientAreaExtended);
+            return S_OK;
+        }
     }
     
     virtual HRESULT GetExtendTitleBarHeight (double*ret) override
     {
-        if(ret == nullptr)
+        START_COM_CALL;
+        
+        @autoreleasepool
         {
-            return E_POINTER;
+            if(ret == nullptr)
+            {
+                return E_POINTER;
+            }
+            
+            *ret = [Window getExtendedTitleBarHeight];
+            
+            return S_OK;
         }
-        
-        *ret = [Window getExtendedTitleBarHeight];
-        
-        return S_OK;
     }
     
     virtual HRESULT SetExtendTitleBarHeight (double value) override
     {
-        [StandardContainer SetTitleBarHeightHint:value];
+        START_COM_CALL;
-        return S_OK;
+        
+        @autoreleasepool
+        {
+            [StandardContainer SetTitleBarHeightHint:value];
+            return S_OK;
+        }
     }
     
     void EnterFullScreenMode ()
     {
         _fullScreenActive = true;
         
-        [Window setHasShadow:YES];
-        [Window setTitleVisibility:NSWindowTitleVisible];
-        [Window setTitlebarAppearsTransparent:NO];
         [Window setTitle:_lastTitle];
-        
-        Window.styleMask = Window.styleMask | NSWindowStyleMaskTitled | NSWindowStyleMaskResizable;
-        Window.styleMask = Window.styleMask & ~NSWindowStyleMaskFullSizeContentView;
-    
         [Window toggleFullScreen:nullptr];
     }
     
@@ -1001,16 +1147,23 @@ private:
     
     virtual HRESULT SetWindowState (AvnWindowState state) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
-            if(_lastWindowState == state)
+            if(Window == nullptr)
+            {
+                return  S_OK;
+            }
+            
+            if(_actualWindowState == state)
             {
                 return S_OK;
             }
             
             _inSetWindowState = true;
             
-            auto currentState = _lastWindowState;
+            auto currentState = _actualWindowState;
             _lastWindowState = state;
             
             if(currentState == Normal)
@@ -1089,8 +1242,12 @@ private:
                         }
                         break;
                 }
+                
+                _actualWindowState = _lastWindowState;
+                WindowEvents->WindowStateChanged(_actualWindowState);
             }
             
+            
             _inSetWindowState = false;
             
             return S_OK;
@@ -1105,6 +1262,11 @@ private:
         }
     }
     
+    virtual bool IsDialog() override
+    {
+        return _isDialog;
+    }
+    
 protected:
     virtual NSWindowStyleMask GetStyle() override
     {
@@ -1184,6 +1346,9 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     [_blurBehind setWantsLayer:true];
     _blurBehind.hidden = true;
     
+    [_blurBehind setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    [_content setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
+    
     [self addSubview:_blurBehind];
     [self addSubview:_content];
     
@@ -1219,9 +1384,6 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     _settingSize = true;
     [super setFrameSize:newSize];
     
-    [_blurBehind setFrameSize:newSize];
-    [_content setFrameSize:newSize];
-    
     auto window = objc_cast<AvnWindow>([self window]);
     
     // TODO get actual titlebar size
@@ -1237,6 +1399,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     [_titleBarMaterial setFrame:tbar];
     tbar.size.height = height < 1 ? 0 : 1;
     [_titleBarUnderline setFrame:tbar];
+
     _settingSize = false;
 }
 
@@ -1264,6 +1427,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     bool _lastKeyHandled;
     AvnPixelSize _lastPixelSize;
     NSObject<IRenderTarget>* _renderTarget;
+    AvnPlatformResizeReason _resizeReason;
 }
 
 - (void)onClosed
@@ -1375,7 +1539,8 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
         _lastPixelSize.Height = (int)fsize.height;
         [self updateRenderTarget];
     
-        _parent->BaseEvents->Resized(AvnSize{newSize.width, newSize.height});
+        auto reason = [self inLiveResize] ? ResizeUser : _resizeReason;
+        _parent->BaseEvents->Resized(AvnSize{newSize.width, newSize.height}, reason);
     }
 }
 
@@ -1541,6 +1706,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
     switch(event.buttonNumber)
     {
+        case 2:
         case 3:
             _isMiddlePressed = true;
             [self mouseEvent:event withType:MiddleButtonDown];
@@ -1573,6 +1739,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 {
     switch(event.buttonNumber)
     {
+        case 2:
         case 3:
             _isMiddlePressed = false;
             [self mouseEvent:event withType:MiddleButtonUp];
@@ -1874,6 +2041,16 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     
 }
 
+- (AvnPlatformResizeReason)getResizeReason
+{
+    return _resizeReason;
+}
+
+- (void)setResizeReason:(AvnPlatformResizeReason)reason
+{
+    _resizeReason = reason;
+}
+
 @end
 
 
@@ -1895,6 +2072,11 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     _isExtended = value;
 }
 
+-(bool) isDialog
+{
+    return _parent->IsDialog();
+}
+
 -(double) getScaling
 {
     return _lastScaling;
@@ -1924,18 +2106,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
 +(void)closeAll
 {
-    NSArray<NSWindow*>* windows = [NSArray arrayWithArray:[NSApp windows]];
+    [[NSApplication sharedApplication] terminate:self];
-    auto numWindows = [windows count];
-    
-    for(int i = 0; i < numWindows; i++)
-    {
-        auto window = (AvnWindow*)[windows objectAtIndex:i];
-        
-        if([window parentWindow] == nullptr) // Avalonia will handle the child windows.
-        {
-            [window performClose:nil];
-        }
-    }
 }
 
 - (void)performClose:(id)sender
@@ -1948,7 +2119,7 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     {
         if(![self windowShouldClose:self]) return;
     }
-    
+
     [self close];
 }
 
@@ -2084,7 +2255,22 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
 
 -(BOOL)canBecomeKeyWindow
 {
-    return _canBecomeKeyAndMain;
+    if (_canBecomeKeyAndMain)
+    {
+        // 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(ch == nil)
+                continue;
+            if (ch.isDialog)
+                return false;
+        }
+        
+        return true;
+    }
+    
+    return false;
 }
 
 -(BOOL)canBecomeMainWindow
@@ -2092,22 +2278,6 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     return _canBecomeKeyAndMain;
 }
 
--(bool) activateAppropriateChild: (bool)activating
-{
-    for(NSWindow* uch in [self childWindows])
-    {
-        auto ch = objc_cast<AvnWindow>(uch);
-        if(ch == nil)
-            continue;
-        [ch activateAppropriateChild:false];
-        return FALSE;
-    }
-    
-    if(!activating)
-        [self makeKeyAndOrderFront:self];
-    return TRUE;
-}
-
 -(bool)shouldTryToHandleEvents
 {
     return _isEnabled;
@@ -2118,26 +2288,15 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     _isEnabled = enable;
 }
 
--(void)makeKeyWindow
-{
-    if([self activateAppropriateChild: true])
-    {
-        [super makeKeyWindow];
-    }
-}
-
 -(void)becomeKeyWindow
 {
     [self showWindowMenuWithAppMenu];
     
-    if([self activateAppropriateChild: true])
+    if(_parent != nullptr)
     {
-        if(_parent != nullptr)
+        _parent->BaseEvents->Activated();
-        {
-            _parent->BaseEvents->Activated();
-        }
     }
-    
+
     [super becomeKeyWindow];
 }
 
@@ -2147,7 +2306,6 @@ NSArray* AllLoopModes = [NSArray arrayWithObjects: NSDefaultRunLoopMode, NSEvent
     if(parent != nil)
     {
         [parent removeChildWindow:self];
-        [parent activateAppropriateChild: false];
     }
 }
 
@@ -2352,13 +2510,14 @@ protected:
         return NSWindowStyleMaskBorderless;
     }
     
-    virtual HRESULT Resize(double x, double y) override
+    virtual HRESULT Resize(double x, double y, AvnPlatformResizeReason reason) override
     {
+        START_COM_CALL;
+        
         @autoreleasepool
         {
             if (Window != nullptr)
             {
-                [StandardContainer setFrameSize:NSSize{x,y}];
                 [Window setContentSize:NSSize{x, y}];
             
                 [Window setFrameTopLeftPoint:ToNSPoint(ConvertPointY(lastPositionSet))];

packages/Avalonia/AvaloniaBuildTasks.targets

@@ -42,12 +42,24 @@
   </Target>
   
   <PropertyGroup>
-    <BuildAvaloniaResourcesDependsOn>$(BuildAvaloniaResourcesDependsOn);AddAvaloniaResources;ResolveReferences</BuildAvaloniaResourcesDependsOn>
+    <BuildAvaloniaResourcesDependsOn>$(BuildAvaloniaResourcesDependsOn);AddAvaloniaResources;ResolveReferences;_GenerateAvaloniaResourcesDependencyCache</BuildAvaloniaResourcesDependsOn>
   </PropertyGroup>
   
+  <Target Name="_GenerateAvaloniaResourcesDependencyCache" BeforeTargets="GenerateAvaloniaResources">
+    <ItemGroup>
+      <CustomAdditionalGenerateAvaloniaResourcesInputs Include="$(IntermediateOutputPath)/Avalonia/Resources.Inputs.cache" />
+    </ItemGroup>
+    
+    <Hash ItemsToHash="@(AvaloniaResource);@(AvaloniaXaml);$(MSBuildAllProjects)">
+      <Output TaskParameter="HashResult" PropertyName="AvaloniaResourcesDependencyHash" />
+    </Hash>
+
+    <WriteLinesToFile Overwrite="true" File="$(IntermediateOutputPath)/Avalonia/Resources.Inputs.cache" Lines="$(AvaloniaResourcesDependencyHash)" WriteOnlyWhenDifferent="True" />
+  </Target>
+  
   <Target Name="GenerateAvaloniaResources" 
           BeforeTargets="CoreCompile;CoreResGen"
-          Inputs="@(AvaloniaResource);@(AvaloniaXaml);$(MSBuildAllProjects)"
+          Inputs="@(AvaloniaResource);@(AvaloniaXaml);@(CustomAdditionalGenerateAvaloniaResourcesInputs);$(MSBuildAllProjects)"
           Outputs="$(AvaloniaResourcesTemporaryFilePath)"
 	  DependsOnTargets="$(BuildAvaloniaResourcesDependsOn)">
     <ItemGroup>

samples/ControlCatalog/MainWindow.xaml.cs

@@ -17,7 +17,10 @@ namespace ControlCatalog
         public MainWindow()
         {
             this.InitializeComponent();
-            this.AttachDevTools();
+            this.AttachDevTools(new Avalonia.Diagnostics.DevToolsOptions()
+            {
+                StartupScreenIndex = 1,
+            });
             //Renderer.DrawFps = true;
             //Renderer.DrawDirtyRects = Renderer.DrawFps = true;
 

samples/ControlCatalog/Pages/ComboBoxPage.xaml

@@ -1,12 +1,20 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="ControlCatalog.Pages.ComboBoxPage"
-             xmlns:sys="clr-namespace:System;assembly=netstandard">
+             xmlns:sys="using:System"
+             xmlns:col="using:System.Collections">
   <StackPanel Orientation="Vertical" Spacing="4">
     <TextBlock Classes="h1">ComboBox</TextBlock>
     <TextBlock Classes="h2">A drop-down list.</TextBlock>
 
-    <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0 16 0 0" Spacing="8">
+    <WrapPanel HorizontalAlignment="Center" Margin="0 16 0 0"
+               MaxWidth="750">
+      <WrapPanel.Styles>
+        <Style Selector="ComboBox">
+          <Setter Property="Width" Value="250" />
+          <Setter Property="Margin" Value="10" />
+        </Style>
+      </WrapPanel.Styles>
       <ComboBox PlaceholderText="Pick an Item">
         <ComboBoxItem>Inline Items</ComboBoxItem>
         <ComboBoxItem>Inline Item 2</ComboBoxItem>
@@ -14,6 +22,24 @@
         <ComboBoxItem>Inline Item 4</ComboBoxItem>
       </ComboBox>
 
+      <ComboBox>
+        <ComboBox.Items>
+          <col:ArrayList>
+            <x:Null />
+            <sys:String>Hello</sys:String>
+            <sys:String>World</sys:String>
+          </col:ArrayList>
+        </ComboBox.Items>
+        <ComboBox.ItemTemplate>
+          <DataTemplate>
+            <Panel>
+              <TextBlock Text="{Binding}" />
+              <TextBlock Text="Null object" IsVisible="{Binding Converter={x:Static ObjectConverters.IsNull}}" />
+            </Panel>
+          </DataTemplate>
+        </ComboBox.ItemTemplate>
+      </ComboBox>
+
       <ComboBox SelectedIndex="0">
         <ComboBoxItem>
           <Panel>
@@ -46,7 +72,7 @@
           <sys:Exception /> 
         </DataValidationErrors.Error>
       </ComboBox>
-    </StackPanel>
+    </WrapPanel>
 
   </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/ContextFlyoutPage.axaml

@@ -1,102 +0,0 @@
-<UserControl xmlns="https://github.com/avaloniaui"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
-             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
-             x:Class="ControlCatalog.Pages.ContextFlyoutPage">
-    <UserControl.Styles>
-        <Style Selector="FlyoutPresenter.NoPadding">
-            <Setter Property="Padding" Value="0" />
-        </Style>
-    </UserControl.Styles>
-    
-    <StackPanel Orientation="Vertical" Spacing="4">
-        <TextBlock Classes="h1">Context Flyout</TextBlock>
-        <TextBlock Classes="h2">A right click Flyout that can be applied to any control.</TextBlock>
-
-        <StackPanel Orientation="Horizontal"
-              Margin="0,16,0,0"
-              HorizontalAlignment="Center"
-              Spacing="16">
-            <Border Background="{DynamicResource SystemAccentColor}"
-                    Margin="16"
-                    Padding="48,48,48,48">
-                <Border.ContextFlyout>
-                    <MenuFlyout>
-                        <MenuItem Header="Standard _Menu Item" InputGesture="Ctrl+A" />
-                        <MenuItem Header="_Disabled Menu Item" IsEnabled="False" InputGesture="Ctrl+D" />
-                        <Separator/>
-                        <MenuItem Header="Menu with _Submenu">
-                            <MenuItem Header="Submenu _1"/>
-                            <MenuItem Header="Submenu _2"/>
-                        </MenuItem>
-                        <MenuItem Header="Menu Item with _Icon" InputGesture="Ctrl+Shift+B">
-                            <MenuItem.Icon>
-                                <Image Source="/Assets/github_icon.png"/>
-                            </MenuItem.Icon>
-                        </MenuItem>
-                        <MenuItem Header="Menu Item with _Checkbox">
-                            <MenuItem.Icon>
-                                <CheckBox BorderThickness="0" IsHitTestVisible="False" IsChecked="True"/>
-                            </MenuItem.Icon>
-                        </MenuItem>
-                    </MenuFlyout>
-                </Border.ContextFlyout>
-                <TextBlock Text="Defined in XAML"/>
-            </Border>
-            <Border Background="{DynamicResource SystemAccentColor}"
-                    Margin="16"
-                    Padding="48,48,48,48">
-                <Border.ContextMenu>
-                    <ContextMenu Items="{Binding MenuItems}">
-                        <ContextMenu.Styles>
-                            <Style Selector="MenuItem">
-                                <Setter Property="Header" Value="{Binding Header}"/>
-                                <Setter Property="Items" Value="{Binding Items}"/>
-                                <Setter Property="Command" Value="{Binding Command}"/>
-                                <Setter Property="CommandParameter" Value="{Binding CommandParameter}"/>
-                            </Style>
-                        </ContextMenu.Styles>
-                    </ContextMenu>
-                </Border.ContextMenu>
-                <TextBlock Text="Dynamically Generated"/>
-            </Border>
-        </StackPanel>
-
-        <TextBlock Text="Custom ContextFlyout for TextBox" />
-
-        <TextBox Name="TextBox" Width="150" HorizontalAlignment="Center" ContextMenu="{x:Null}">
-            <TextBox.ContextFlyout>
-                <Flyout FlyoutPresenterClasses="NoPadding">
-                    <StackPanel Orientation="Horizontal">
-                        <StackPanel.Styles>
-                            <Style Selector="Button">
-                                <Setter Property="Background" Value="Transparent" />
-                                <Setter Property="Height" Value="40" />
-                                <Setter Property="Width" Value="40" />
-                                <Setter Property="VerticalContentAlignment" Value="Center" />
-                            </Style>
-                            <Style Selector="Button:disabled /template/ ContentPresenter#PART_ContentPresenter">
-                                <Setter Property="Background" Value="Transparent" />
-                                <Setter Property="Opacity" Value="0.5" />
-                            </Style>
-                        </StackPanel.Styles>
-                        <Button Name="CutButton" Command="{Binding $parent[TextBox].Cut}" IsEnabled="{Binding $parent[TextBox].CanCut}">
-                            <PathIcon Width="14" Height="14" Data="M5.22774,2.08072 C5.43359778,1.94704 5.7011484,1.98419259 5.86368634,2.15675215 L5.91939,2.22774 L12.5191,12.3904 C12.956,12.1419 13.4614,12.0000019 14,12.0000019 C15.6569,12.0000019 17,13.3431 17,15.0000019 C17,16.6569 15.6569,18.0000019 14,18.0000019 C12.3431,18.0000019 11,16.6569 11,15.0000019 C11,14.3201402 11.226152,13.693011 11.6073785,13.1899092 L11.7401,13.0269 L10,10.3474 L8.25991,13.0269 C8.72078,13.5543 9,14.2446 9,15.0000019 C9,16.6569 7.65685,18.0000019 6,18.0000019 C4.34315,18.0000019 3,16.6569 3,15.0000019 C3,13.3431 4.34315,12.0000019 6,12.0000019 C6.46163143,12.0000019 6.89890041,12.1042536 7.28955831,12.2905296 L7.4809,12.3904 L9.40382,9.42936 L5.08072,2.77238 C4.93033,2.54079 4.99615,2.23112 5.22774,2.08072 Z M14,13 C12.8954,13 12,13.8954 12,15 C12,16.1046 12.8954,17 14,17 C15.1046,17 16,16.1046 16,15 C16,13.8954 15.1046,13 14,13 Z M6,13 C4.89543,13 4,13.8954 4,15 C4,16.1046 4.89543,17 6,17 C7.10457,17 8,16.1046 8,15 C8,13.8954 7.10457,13 6,13 Z M14.7723,2.08072 C15.0039,2.23112 15.0697,2.54079 14.9193,2.77238 L11.1924,8.51133 L10.5962,7.59329 L14.0806,2.22774 C14.231,1.99615 14.5407,1.93033 14.7723,2.08072 Z" />
-                        </Button>
-                        <Button Name="CopyButton" Content="Copy" Command="{Binding $parent[TextBox].Copy}" IsEnabled="{Binding $parent[TextBox].CanCopy}">
-                            <PathIcon Width="14" Height="14" Data="M5.50280381,4.62704038 L5.5,6.75 L5.5,17.2542087 C5.5,19.0491342 6.95507456,20.5042087 8.75,20.5042087 L17.3662868,20.5044622 C17.057338,21.3782241 16.2239751,22.0042087 15.2444057,22.0042087 L8.75,22.0042087 C6.12664744,22.0042087 4,19.8775613 4,17.2542087 L4,6.75 C4,5.76928848 4.62744523,4.93512464 5.50280381,4.62704038 Z M17.75,2 C18.9926407,2 20,3.00735931 20,4.25 L20,17.25 C20,18.4926407 18.9926407,19.5 17.75,19.5 L8.75,19.5 C7.50735931,19.5 6.5,18.4926407 6.5,17.25 L6.5,4.25 C6.5,3.00735931 7.50735931,2 8.75,2 L17.75,2 Z M17.75,3.5 L8.75,3.5 C8.33578644,3.5 8,3.83578644 8,4.25 L8,17.25 C8,17.6642136 8.33578644,18 8.75,18 L17.75,18 C18.1642136,18 18.5,17.6642136 18.5,17.25 L18.5,4.25 C18.5,3.83578644 18.1642136,3.5 17.75,3.5 Z" />
-                        </Button>
-                        <Button Name="PasteButton" Content="Paste" Command="{Binding $parent[TextBox].Paste}" IsEnabled="{Binding $parent[TextBox].CanPaste}">
-                            <PathIcon Width="14" Height="14" Data="M13.75,2 C14.940864,2 15.9156449,2.92516159 15.9948092,4.09595119 L16,4.25 L16,4.25 C16,4.16530567 15.9953205,4.0817043 15.9862059,3.99944035 L17.75,4 C18.9926407,4 20,5.00735931 20,6.25 L20,19.75 C20,20.9926407 18.9926407,22 17.75,22 L6.25,22 C5.00735931,22 4,20.9926407 4,19.75 L4,6.25 C4,5.00735931 5.00735931,4 6.25,4 L8.01379413,3.99944035 C8.00733496,4.05773764 8.00310309,4.11670658 8.00118552,4.17626017 L8,4.25 C8,3.00735931 9.00735931,2 10.25,2 L13.75,2 Z M13.75,6.5 L10.25,6.5 C9.45594921,6.5 8.75796956,6.08867052 8.357512,5.4674625 L8.37902077,5.50019943 L8.37902077,5.50019943 L6.25,5.5 C5.83578644,5.5 5.5,5.83578644 5.5,6.25 L5.5,19.75 C5.5,20.1642136 5.83578644,20.5 6.25,20.5 L17.75,20.5 C18.1642136,20.5 18.5,20.1642136 18.5,19.75 L18.5,6.25 C18.5,5.83578644 18.1642136,5.5 17.75,5.5 L15.6209792,5.50019943 L15.642488,5.4674625 C15.2420304,6.08867052 14.5440508,6.5 13.75,6.5 Z M13.75,3.5 L10.25,3.5 C9.83578644,3.5 9.5,3.83578644 9.5,4.25 C9.5,4.66421356 9.83578644,5 10.25,5 L13.75,5 C14.1642136,5 14.5,4.66421356 14.5,4.25 C14.5,3.83578644 14.1642136,3.5 13.75,3.5 Z" />
-                        </Button>
-                        <Button Name="ClearButton" Content="Clear" Command="{Binding $parent[TextBox].Clear}">
-                            <PathIcon Width="14" Height="14" Data="M3.52499419,3.71761187 L3.61611652,3.61611652 C4.0717282,3.16050485 4.79154862,3.13013074 5.28238813,3.52499419 L5.38388348,3.61611652 L14,12.233 L22.6161165,3.61611652 C23.1042719,3.12796116 23.8957281,3.12796116 24.3838835,3.61611652 C24.8720388,4.10427189 24.8720388,4.89572811 24.3838835,5.38388348 L15.767,14 L24.3838835,22.6161165 C24.8394952,23.0717282 24.8698693,23.7915486 24.4750058,24.2823881 L24.3838835,24.3838835 C23.9282718,24.8394952 23.2084514,24.8698693 22.7176119,24.4750058 L22.6161165,24.3838835 L14,15.767 L5.38388348,24.3838835 C4.89572811,24.8720388 4.10427189,24.8720388 3.61611652,24.3838835 C3.12796116,23.8957281 3.12796116,23.1042719 3.61611652,22.6161165 L12.233,14 L3.61611652,5.38388348 C3.16050485,4.9282718 3.13013074,4.20845138 3.52499419,3.71761187 L3.61611652,3.61611652 L3.52499419,3.71761187 Z" />
-                        </Button>
-                    </StackPanel>
-                </Flyout>
-            </TextBox.ContextFlyout>
-        </TextBox>
-    
-    </StackPanel>
-</UserControl>

samples/ControlCatalog/Pages/ContextFlyoutPage.axaml.cs

@@ -1,45 +0,0 @@
-using Avalonia;
-using Avalonia.Controls;
-using Avalonia.Markup.Xaml;
-using ControlCatalog.ViewModels;
-using Avalonia.Interactivity;
-namespace ControlCatalog.Pages
-{
-    public class ContextFlyoutPage : UserControl
-    {
-        private TextBox _textBox;
-
-        public ContextFlyoutPage()
-        {
-            InitializeComponent();
-
-            var vm = new ContextFlyoutPageViewModel();
-            vm.View = this;
-            DataContext = vm;
-
-            _textBox = this.FindControl<TextBox>("TextBox");
-
-            var cutButton = this.FindControl<Button>("CutButton");
-            cutButton.Click += CloseFlyout;
-
-            var copyButton = this.FindControl<Button>("CopyButton");
-            copyButton.Click += CloseFlyout;
-
-            var pasteButton = this.FindControl<Button>("PasteButton");
-            pasteButton.Click += CloseFlyout;
-
-            var clearButton = this.FindControl<Button>("ClearButton");
-            clearButton.Click += CloseFlyout;
-        }
-
-        private void CloseFlyout(object sender, RoutedEventArgs e)
-        {
-            _textBox.ContextFlyout.Hide();
-        }
-
-        private void InitializeComponent()
-        {
-            AvaloniaXamlLoader.Load(this);
-        }
-    }
-}

samples/ControlCatalog/Pages/ContextFlyoutPage.xaml

@@ -0,0 +1,157 @@
+<UserControl x:Class="ControlCatalog.Pages.ContextFlyoutPage"
+             xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             d:DesignHeight="450"
+             d:DesignWidth="800"
+             mc:Ignorable="d">
+  <UserControl.Styles>
+    <Style Selector="FlyoutPresenter.NoPadding">
+      <Setter Property="Padding" Value="0" />
+    </Style>
+  </UserControl.Styles>
+
+  <StackPanel Orientation="Vertical" Spacing="4">
+    <StackPanel.Styles>
+      <Style Selector="Border.context-target">
+        <Setter Property="Padding" Value="48,20" />
+        <Setter Property="Margin" Value="8" />
+        <Setter Property="Focusable" Value="True" />
+        <Setter Property="Background" Value="{DynamicResource SystemAccentColor}" />
+      </Style>
+      <Style Selector="Border.context-target > :is(Control)">
+        <Setter Property="VerticalAlignment" Value="Center" />
+      </Style>
+    </StackPanel.Styles>
+    <TextBlock Classes="h1">Context Flyout</TextBlock>
+    <TextBlock Classes="h2">A right click Flyout that can be applied to any control.</TextBlock>
+
+    <UniformGrid HorizontalAlignment="Center" Rows="2">
+      <Border Classes="context-target">
+        <Border.ContextFlyout>
+          <MenuFlyout>
+            <MenuItem Header="Standard _Menu Item" InputGesture="Ctrl+A" />
+            <MenuItem Header="_Disabled Menu Item"
+                      InputGesture="Ctrl+D"
+                      IsEnabled="False" />
+            <Separator />
+            <MenuItem Header="Menu with _Submenu">
+              <MenuItem Header="Submenu _1" />
+              <MenuItem Header="Submenu _2" />
+            </MenuItem>
+            <MenuItem Header="Menu Item with _Icon" InputGesture="Ctrl+Shift+B">
+              <MenuItem.Icon>
+                <Image Source="/Assets/github_icon.png" />
+              </MenuItem.Icon>
+            </MenuItem>
+            <MenuItem Header="Menu Item with _Checkbox">
+              <MenuItem.Icon>
+                <CheckBox BorderThickness="0"
+                          IsChecked="True"
+                          IsHitTestVisible="False" />
+              </MenuItem.Icon>
+            </MenuItem>
+          </MenuFlyout>
+        </Border.ContextFlyout>
+        <TextBlock Text="Defined in XAML" />
+      </Border>
+      <Border Classes="context-target">
+        <Border.Styles>
+          <Style Selector="MenuFlyoutPresenter MenuItem">
+            <Setter Property="Header" Value="{Binding Header}"/>
+            <Setter Property="Items" Value="{Binding Items}"/>
+            <Setter Property="Command" Value="{Binding Command}"/>
+            <Setter Property="CommandParameter" Value="{Binding CommandParameter}"/>
+          </Style>
+        </Border.Styles>
+        <Border.ContextFlyout>
+          <MenuFlyout Items="{Binding MenuItems}" />
+        </Border.ContextFlyout>
+        <TextBlock Text="Dynamically Generated"/>
+      </Border>
+      <Border x:Name="CustomContextRequestedBorder"
+              Classes="context-target">
+        <Border.ContextFlyout>
+          <Flyout Content="Should never be visible" />
+        </Border.ContextFlyout>
+        <TextBlock Text="Custom ContextRequested handler" TextWrapping="Wrap" />
+      </Border>
+      <Border x:Name="CancellableContextBorder"
+              Classes="context-target">
+        <Border.ContextFlyout>
+          <Flyout>
+            <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
+          </Flyout>
+        </Border.ContextFlyout>
+        <StackPanel>
+          <TextBlock Text="Cancellable" />
+          <CheckBox x:Name="CancelOpenCheckBox" Content="Cancel open" />
+        </StackPanel>
+      </Border>
+    </UniformGrid>
+
+    <TextBlock Text="Custom ContextFlyout for TextBox" />
+
+    <TextBox Name="TextBox"
+             Width="150"
+             HorizontalAlignment="Center"
+             ContextMenu="{x:Null}">
+      <TextBox.ContextFlyout>
+        <Flyout FlyoutPresenterClasses="NoPadding">
+          <StackPanel>
+          <StackPanel Orientation="Horizontal">
+            <StackPanel.Styles>
+              <Style Selector="Button">
+                <Setter Property="Background" Value="Transparent" />
+                <Setter Property="Height" Value="40" />
+                <Setter Property="Width" Value="40" />
+                <Setter Property="VerticalContentAlignment" Value="Center" />
+              </Style>
+              <Style Selector="Button:disabled /template/ ContentPresenter#PART_ContentPresenter">
+                <Setter Property="Background" Value="Transparent" />
+                <Setter Property="Opacity" Value="0.5" />
+              </Style>
+            </StackPanel.Styles>
+            <Button Name="CutButton"
+                    Command="{Binding $parent[TextBox].Cut}"
+                    IsEnabled="{Binding $parent[TextBox].CanCut}">
+              <PathIcon Width="14"
+                        Height="14"
+                        Data="M5.22774,2.08072 C5.43359778,1.94704 5.7011484,1.98419259 5.86368634,2.15675215 L5.91939,2.22774 L12.5191,12.3904 C12.956,12.1419 13.4614,12.0000019 14,12.0000019 C15.6569,12.0000019 17,13.3431 17,15.0000019 C17,16.6569 15.6569,18.0000019 14,18.0000019 C12.3431,18.0000019 11,16.6569 11,15.0000019 C11,14.3201402 11.226152,13.693011 11.6073785,13.1899092 L11.7401,13.0269 L10,10.3474 L8.25991,13.0269 C8.72078,13.5543 9,14.2446 9,15.0000019 C9,16.6569 7.65685,18.0000019 6,18.0000019 C4.34315,18.0000019 3,16.6569 3,15.0000019 C3,13.3431 4.34315,12.0000019 6,12.0000019 C6.46163143,12.0000019 6.89890041,12.1042536 7.28955831,12.2905296 L7.4809,12.3904 L9.40382,9.42936 L5.08072,2.77238 C4.93033,2.54079 4.99615,2.23112 5.22774,2.08072 Z M14,13 C12.8954,13 12,13.8954 12,15 C12,16.1046 12.8954,17 14,17 C15.1046,17 16,16.1046 16,15 C16,13.8954 15.1046,13 14,13 Z M6,13 C4.89543,13 4,13.8954 4,15 C4,16.1046 4.89543,17 6,17 C7.10457,17 8,16.1046 8,15 C8,13.8954 7.10457,13 6,13 Z M14.7723,2.08072 C15.0039,2.23112 15.0697,2.54079 14.9193,2.77238 L11.1924,8.51133 L10.5962,7.59329 L14.0806,2.22774 C14.231,1.99615 14.5407,1.93033 14.7723,2.08072 Z" />
+            </Button>
+            <Button Name="CopyButton"
+                    Command="{Binding $parent[TextBox].Copy}"
+                    IsEnabled="{Binding $parent[TextBox].CanCopy}">
+              <PathIcon Width="14"
+                        Height="14"
+                        Data="M5.50280381,4.62704038 L5.5,6.75 L5.5,17.2542087 C5.5,19.0491342 6.95507456,20.5042087 8.75,20.5042087 L17.3662868,20.5044622 C17.057338,21.3782241 16.2239751,22.0042087 15.2444057,22.0042087 L8.75,22.0042087 C6.12664744,22.0042087 4,19.8775613 4,17.2542087 L4,6.75 C4,5.76928848 4.62744523,4.93512464 5.50280381,4.62704038 Z M17.75,2 C18.9926407,2 20,3.00735931 20,4.25 L20,17.25 C20,18.4926407 18.9926407,19.5 17.75,19.5 L8.75,19.5 C7.50735931,19.5 6.5,18.4926407 6.5,17.25 L6.5,4.25 C6.5,3.00735931 7.50735931,2 8.75,2 L17.75,2 Z M17.75,3.5 L8.75,3.5 C8.33578644,3.5 8,3.83578644 8,4.25 L8,17.25 C8,17.6642136 8.33578644,18 8.75,18 L17.75,18 C18.1642136,18 18.5,17.6642136 18.5,17.25 L18.5,4.25 C18.5,3.83578644 18.1642136,3.5 17.75,3.5 Z" />
+            </Button>
+            <Button Name="PasteButton"
+                    Command="{Binding $parent[TextBox].Paste}"
+                    IsEnabled="{Binding $parent[TextBox].CanPaste}">
+              <PathIcon Width="14"
+                        Height="14"
+                        Data="M13.75,2 C14.940864,2 15.9156449,2.92516159 15.9948092,4.09595119 L16,4.25 L16,4.25 C16,4.16530567 15.9953205,4.0817043 15.9862059,3.99944035 L17.75,4 C18.9926407,4 20,5.00735931 20,6.25 L20,19.75 C20,20.9926407 18.9926407,22 17.75,22 L6.25,22 C5.00735931,22 4,20.9926407 4,19.75 L4,6.25 C4,5.00735931 5.00735931,4 6.25,4 L8.01379413,3.99944035 C8.00733496,4.05773764 8.00310309,4.11670658 8.00118552,4.17626017 L8,4.25 C8,3.00735931 9.00735931,2 10.25,2 L13.75,2 Z M13.75,6.5 L10.25,6.5 C9.45594921,6.5 8.75796956,6.08867052 8.357512,5.4674625 L8.37902077,5.50019943 L8.37902077,5.50019943 L6.25,5.5 C5.83578644,5.5 5.5,5.83578644 5.5,6.25 L5.5,19.75 C5.5,20.1642136 5.83578644,20.5 6.25,20.5 L17.75,20.5 C18.1642136,20.5 18.5,20.1642136 18.5,19.75 L18.5,6.25 C18.5,5.83578644 18.1642136,5.5 17.75,5.5 L15.6209792,5.50019943 L15.642488,5.4674625 C15.2420304,6.08867052 14.5440508,6.5 13.75,6.5 Z M13.75,3.5 L10.25,3.5 C9.83578644,3.5 9.5,3.83578644 9.5,4.25 C9.5,4.66421356 9.83578644,5 10.25,5 L13.75,5 C14.1642136,5 14.5,4.66421356 14.5,4.25 C14.5,3.83578644 14.1642136,3.5 13.75,3.5 Z" />
+            </Button>
+            <Button Name="ClearButton" Command="{Binding $parent[TextBox].Clear}">
+              <PathIcon Width="14"
+                        Height="14"
+                        Data="M3.52499419,3.71761187 L3.61611652,3.61611652 C4.0717282,3.16050485 4.79154862,3.13013074 5.28238813,3.52499419 L5.38388348,3.61611652 L14,12.233 L22.6161165,3.61611652 C23.1042719,3.12796116 23.8957281,3.12796116 24.3838835,3.61611652 C24.8720388,4.10427189 24.8720388,4.89572811 24.3838835,5.38388348 L15.767,14 L24.3838835,22.6161165 C24.8394952,23.0717282 24.8698693,23.7915486 24.4750058,24.2823881 L24.3838835,24.3838835 C23.9282718,24.8394952 23.2084514,24.8698693 22.7176119,24.4750058 L22.6161165,24.3838835 L14,15.767 L5.38388348,24.3838835 C4.89572811,24.8720388 4.10427189,24.8720388 3.61611652,24.3838835 C3.12796116,23.8957281 3.12796116,23.1042719 3.61611652,22.6161165 L12.233,14 L3.61611652,5.38388348 C3.16050485,4.9282718 3.13013074,4.20845138 3.52499419,3.71761187 L3.61611652,3.61611652 L3.52499419,3.71761187 Z" />
+            </Button>
+          </StackPanel>
+            <Border Classes="context-target"
+                    Padding="4, 20">
+              <Border.ContextFlyout>
+                <Flyout>
+                  <TextBlock>Hello world</TextBlock>
+                </Flyout>
+              </Border.ContextFlyout>
+              <TextBlock>Inner context flyout</TextBlock>
+            </Border>
+          </StackPanel>
+        </Flyout>
+      </TextBox.ContextFlyout>
+    </TextBox>
+  </StackPanel>
+</UserControl>

samples/ControlCatalog/Pages/ContextFlyoutPage.xaml.cs

@@ -0,0 +1,91 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml;
+using ControlCatalog.ViewModels;
+using Avalonia.Interactivity;
+using System;
+using System.ComponentModel;
+
+namespace ControlCatalog.Pages
+{
+    public class ContextFlyoutPage : UserControl
+    {
+        private TextBox _textBox;
+
+        public ContextFlyoutPage()
+        {
+            InitializeComponent();
+
+            DataContext = new ContextPageViewModel();
+
+            _textBox = this.FindControl<TextBox>("TextBox");
+
+            var cutButton = this.FindControl<Button>("CutButton");
+            cutButton.Click += CloseFlyout;
+
+            var copyButton = this.FindControl<Button>("CopyButton");
+            copyButton.Click += CloseFlyout;
+
+            var pasteButton = this.FindControl<Button>("PasteButton");
+            pasteButton.Click += CloseFlyout;
+
+            var clearButton = this.FindControl<Button>("ClearButton");
+            clearButton.Click += CloseFlyout;
+
+            var customContextRequestedBorder = this.FindControl<Border>("CustomContextRequestedBorder");
+            customContextRequestedBorder.AddHandler(ContextRequestedEvent, CustomContextRequested, RoutingStrategies.Tunnel);
+
+            var cancellableContextBorder = this.FindControl<Border>("CancellableContextBorder");
+            cancellableContextBorder.ContextFlyout!.Closing += ContextFlyoutPage_Closing;
+            cancellableContextBorder.ContextFlyout!.Opening += ContextFlyoutPage_Opening;
+        }
+
+        private ContextPageViewModel _model;
+        protected override void OnDataContextChanged(EventArgs e)
+        {
+            if (_model != null)
+                _model.View = null;
+            _model = DataContext as ContextPageViewModel;
+            if (_model != null)
+                _model.View = this;
+
+            base.OnDataContextChanged(e);
+        }
+
+        private void ContextFlyoutPage_Closing(object sender, CancelEventArgs e)
+        {
+            var cancelCloseCheckBox = this.FindControl<CheckBox>("CancelCloseCheckBox");
+            e.Cancel = cancelCloseCheckBox.IsChecked ?? false;
+        }
+
+        private void ContextFlyoutPage_Opening(object sender, EventArgs e)
+        {
+            if (e is CancelEventArgs cancelArgs)
+            {
+                var cancelCloseCheckBox = this.FindControl<CheckBox>("CancelOpenCheckBox");
+                cancelArgs.Cancel = cancelCloseCheckBox.IsChecked ?? false;
+            }
+        }
+
+        private void CloseFlyout(object sender, RoutedEventArgs e)
+        {
+            _textBox.ContextFlyout.Hide();
+        }
+
+        public void CustomContextRequested(object sender, ContextRequestedEventArgs e)
+        {
+            var border = (Border)sender;
+            var textBlock = (TextBlock)border.Child;
+
+            textBlock.Text = e.TryGetPosition(border, out var point)
+                ? $"Context was requested with pointer at: {point.X:N0}, {point.Y:N0}"
+                : "Context was requested without pointer";
+            e.Handled = true;
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+    }
+}

samples/ControlCatalog/Pages/ContextMenuPage.xaml

@@ -1,58 +1,88 @@
-<UserControl xmlns="https://github.com/avaloniaui"
+<UserControl x:Class="ControlCatalog.Pages.ContextMenuPage"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns="https://github.com/avaloniaui"
-             x:Class="ControlCatalog.Pages.ContextMenuPage">
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
-    <StackPanel Orientation="Vertical" Spacing="4">
+  <StackPanel Orientation="Vertical" Spacing="4">
-        <TextBlock Classes="h1">Context Menu</TextBlock>
+    <TextBlock Classes="h1">Context Menu</TextBlock>
-        <TextBlock Classes="h2">A right click menu that can be applied to any control.</TextBlock>
+    <TextBlock Classes="h2">A right click menu that can be applied to any control.</TextBlock>
 
-        <StackPanel Orientation="Horizontal"
+    <UniformGrid HorizontalAlignment="Center" Rows="2">
-              Margin="0,16,0,0"
+      <UniformGrid.Styles>
-              HorizontalAlignment="Center"
+        <Style Selector="UniformGrid > Border">
-              Spacing="16">
+          <Setter Property="Padding" Value="48,20" />
-            <Border Background="{DynamicResource SystemAccentColor}"
+          <Setter Property="Margin" Value="8" />
-                    Margin="16"
+          <Setter Property="Focusable" Value="True" />
-                    Padding="48,48,48,48">
+          <Setter Property="Background" Value="{DynamicResource SystemAccentColor}" />
-                <Border.ContextMenu>
+        </Style>
-                    <ContextMenu>
+        <Style Selector="UniformGrid > Border > :is(Control)">
-                        <MenuItem Header="Standard _Menu Item" InputGesture="Ctrl+A" />
+          <Setter Property="VerticalAlignment" Value="Center" />
-                        <MenuItem Header="_Disabled Menu Item" IsEnabled="False" InputGesture="Ctrl+D" />
+        </Style>
-                        <Separator/>
+      </UniformGrid.Styles>
-                        <MenuItem Header="Menu with _Submenu">
+      <Border>
-                            <MenuItem Header="Submenu _1"/>
+        <Border.ContextMenu>
-                            <MenuItem Header="Submenu _2"/>
+          <ContextMenu>
-                        </MenuItem>
+            <MenuItem Header="Standard _Menu Item" InputGesture="Ctrl+A" />
-                        <MenuItem Header="Menu Item with _Icon" InputGesture="Ctrl+Shift+B">
+            <MenuItem Header="_Disabled Menu Item"
-                            <MenuItem.Icon>
+                      InputGesture="Ctrl+D"
-                                <Image Source="/Assets/github_icon.png"/>
+                      IsEnabled="False" />
-                            </MenuItem.Icon>
+            <Separator />
-                        </MenuItem>
+            <MenuItem Header="Menu with _Submenu">
-                        <MenuItem Header="Menu Item with _Checkbox">
+              <MenuItem Header="Submenu _1" />
-                            <MenuItem.Icon>
+              <MenuItem Header="Submenu _2" />
-                                <CheckBox BorderThickness="0" IsHitTestVisible="False" IsChecked="True"/>
+            </MenuItem>
-                            </MenuItem.Icon>
+            <MenuItem Header="Menu Item with _Icon" InputGesture="Ctrl+Shift+B">
-                        </MenuItem>
+              <MenuItem.Icon>
-                        <MenuItem Header="Menu Item that won't close on click" StaysOpenOnClick="True" />
+                <Image Source="/Assets/github_icon.png" />
-                    </ContextMenu>
+              </MenuItem.Icon>
-                </Border.ContextMenu>
+            </MenuItem>
-                <TextBlock Text="Defined in XAML"/>
+            <MenuItem Header="Menu Item with _Checkbox">
-            </Border>
+              <MenuItem.Icon>
-            <Border Background="{DynamicResource SystemAccentColor}"
+                <CheckBox BorderThickness="0"
-                    Margin="16"
+                          IsChecked="True"
-                    Padding="48,48,48,48">
+                          IsHitTestVisible="False" />
-                <Border.ContextMenu>
+              </MenuItem.Icon>
-                    <ContextMenu Items="{Binding MenuItems}">
+            </MenuItem>
-                        <ContextMenu.Styles>
+            <MenuItem Header="Menu Item that won't close on click" StaysOpenOnClick="True" />
-                            <Style Selector="MenuItem">
+          </ContextMenu>
-                                <Setter Property="Header" Value="{Binding Header}"/>
+        </Border.ContextMenu>
-                                <Setter Property="Items" Value="{Binding Items}"/>
+        <TextBlock Text="Defined in XAML" />
-                                <Setter Property="Command" Value="{Binding Command}"/>
+      </Border>
-                                <Setter Property="CommandParameter" Value="{Binding CommandParameter}"/>
+      <Border>
-                            </Style>
+        <Border.Styles>
-                        </ContextMenu.Styles>
+          <Style Selector="ContextMenu MenuItem">
-                    </ContextMenu>
+            <Setter Property="Header" Value="{Binding Header}"/>
-                </Border.ContextMenu>
+            <Setter Property="Items" Value="{Binding Items}"/>
-                <TextBlock Text="Dynamically Generated"/>
+            <Setter Property="Command" Value="{Binding Command}"/>
-            </Border>
+            <Setter Property="CommandParameter" Value="{Binding CommandParameter}"/>
+          </Style>
+        </Border.Styles>
+        <Border.ContextMenu>
+          <ContextMenu Items="{Binding MenuItems}" />
+        </Border.ContextMenu>
+        <TextBlock Text="Dynamically Generated"/>
+      </Border>
+      <Border x:Name="CustomContextRequestedBorder">
+        <Border.ContextMenu>
+          <ContextMenu>
+            <MenuItem Header="Should never be visible" />
+          </ContextMenu>
+        </Border.ContextMenu>
+        <TextBlock Text="Custom ContextRequested handler" TextWrapping="Wrap" />
+      </Border>
+      <Border x:Name="CancellableContextBorder">
+        <Border.ContextMenu>
+          <ContextMenu>
+            <MenuItem>
+              <MenuItem.Header>
+                <CheckBox x:Name="CancelCloseCheckBox" Content="Cancel close" />
+              </MenuItem.Header>
+            </MenuItem>
+          </ContextMenu>
+        </Border.ContextMenu>
+        <StackPanel>
+          <TextBlock Text="Cancellable" />
+          <CheckBox x:Name="CancelOpenCheckBox" Content="Cancel open" />
         </StackPanel>
-    </StackPanel>
+      </Border>
+    </UniformGrid>
+  </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/ContextMenuPage.xaml.cs

@@ -1,5 +1,8 @@
 using System;
+using System.ComponentModel;
+
 using Avalonia.Controls;
+using Avalonia.Interactivity;
 using Avalonia.Markup.Xaml;
 using ControlCatalog.ViewModels;
 
@@ -10,21 +13,54 @@ namespace ControlCatalog.Pages
         public ContextMenuPage()
         {
             this.InitializeComponent();
-            DataContext = new ContextMenuPageViewModel();
+            DataContext = new ContextPageViewModel();
+
+            var customContextRequestedBorder = this.FindControl<Border>("CustomContextRequestedBorder");
+            customContextRequestedBorder.AddHandler(ContextRequestedEvent, CustomContextRequested, RoutingStrategies.Tunnel);
+
+            var cancellableContextBorder = this.FindControl<Border>("CancellableContextBorder");
+            cancellableContextBorder.ContextMenu!.ContextMenuClosing += ContextFlyoutPage_Closing;
+            cancellableContextBorder.ContextMenu!.ContextMenuOpening += ContextFlyoutPage_Opening;
         }
 
-        private ContextMenuPageViewModel _model;
+        private ContextPageViewModel _model;
         protected override void OnDataContextChanged(EventArgs e)
         {
             if (_model != null)
                 _model.View = null;
-            _model  = DataContext as ContextMenuPageViewModel;
+            _model  = DataContext as ContextPageViewModel;
             if (_model != null)
                 _model.View = this;
 
             base.OnDataContextChanged(e);
         }
 
+        private void ContextFlyoutPage_Closing(object sender, CancelEventArgs e)
+        {
+            var cancelCloseCheckBox = this.FindControl<CheckBox>("CancelCloseCheckBox");
+            e.Cancel = cancelCloseCheckBox.IsChecked ?? false;
+        }
+
+        private void ContextFlyoutPage_Opening(object sender, EventArgs e)
+        {
+            if (e is CancelEventArgs cancelArgs)
+            {
+                var cancelCloseCheckBox = this.FindControl<CheckBox>("CancelOpenCheckBox");
+                cancelArgs.Cancel = cancelCloseCheckBox.IsChecked ?? false;
+            }
+        }
+
+        public void CustomContextRequested(object sender, ContextRequestedEventArgs e)
+        {
+            var border = (Border)sender;
+            var textBlock = (TextBlock)border.Child;
+
+            textBlock.Text = e.TryGetPosition(border, out var point)
+                ? $"Context was requested with pointer at: {point.X:N0}, {point.Y:N0}"
+                : "Context was requested without pointer";
+            e.Handled = true;
+        }
+
         private void InitializeComponent()
         {
             AvaloniaXamlLoader.Load(this);

samples/ControlCatalog/Pages/DataGridPage.xaml

@@ -23,16 +23,21 @@
     </StackPanel>
     <TabControl Grid.Row="2">
       <TabItem Header="DataGrid">
-        <DataGrid Name="dataGrid1" Margin="12" CanUserResizeColumns="True" CanUserReorderColumns="True" CanUserSortColumns="True" HeadersVisibility="All">
+        <DockPanel>
-          <DataGrid.Columns>
+          <CheckBox x:Name="ShowGDP"  IsChecked="True"  Content="Toggle GDP Column Visibility"
-            <DataGridTextColumn Header="Country" Binding="{Binding Name}" Width="6*" />
+                    DockPanel.Dock="Top"/>
-            <!-- CompiledBinding example of usage. -->
+          <DataGrid Name="dataGrid1" Margin="12" CanUserResizeColumns="True" CanUserReorderColumns="True" CanUserSortColumns="True" HeadersVisibility="All">
-            <DataGridTextColumn Header="Region" Binding="{CompiledBinding Region}" Width="4*" x:DataType="local:Country" />
+            <DataGrid.Columns>
-            <DataGridTextColumn Header="Population" Binding="{Binding Population}" Width="3*" />
+              <DataGridTextColumn Header="Country" Binding="{Binding Name}" Width="6*" MinWidth="400"  />
-            <DataGridTextColumn Header="Area" Binding="{Binding Area}" Width="3*" />
+              <!-- CompiledBinding example of usage. -->
-            <DataGridTextColumn Header="GDP" Binding="{Binding GDP}" Width="3*" CellStyleClasses="gdp" />
+              <DataGridTextColumn Header="Region" Binding="{CompiledBinding Region}" Width="4*" x:DataType="local:Country" />
-          </DataGrid.Columns>
+              <DataGridTextColumn Header="Population" Binding="{Binding Population}" Width="3*" />
-        </DataGrid>
+              <DataGridTextColumn Header="Area" Binding="{Binding Area}" Width="3*" />
+              <DataGridTextColumn Header="GDP" Binding="{Binding GDP}" Width="3*" CellStyleClasses="gdp"
+                                  IsVisible="{Binding #ShowGDP.IsChecked}"/>
+            </DataGrid.Columns>
+          </DataGrid>
+        </DockPanel>
       </TabItem>
       <TabItem Header="Grouping">
         <DataGrid Name="dataGridGrouping" Margin="12">

samples/ControlCatalog/Pages/NumericUpDownPage.xaml

@@ -2,7 +2,8 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:sys="clr-namespace:System;assembly=netstandard"
              x:Class="ControlCatalog.Pages.NumericUpDownPage">
-  <StackPanel Orientation="Vertical" Spacing="4">
+  <StackPanel Orientation="Vertical" Spacing="4"
+              MaxWidth="800">
     <TextBlock Margin="2" Classes="h1">Numeric up-down control</TextBlock>
     <TextBlock Margin="2" Classes="h2" TextWrapping="Wrap">Numeric up-down control provides a TextBox with button spinners that allow incrementing and decrementing numeric values by using the spinner buttons, keyboard up/down arrows, or mouse wheel.</TextBlock>
 
@@ -68,24 +69,36 @@
         <NumericUpDown Grid.Row="3" Grid.Column="1" Value="{Binding #upDown.Value}" VerticalAlignment="Center"
                        Margin="2" HorizontalAlignment="Center"/>
 
+
       </Grid>
     </Grid>
 
-    <StackPanel Margin="2,10,2,2" Orientation="Horizontal" Spacing="10">
+    <WrapPanel Margin="2,10,2,2">
-      <TextBlock FontSize="14" FontWeight="Bold" VerticalAlignment="Center">Usage of NumericUpDown:</TextBlock>
+      <StackPanel Orientation="Vertical" Margin="10">
-      <NumericUpDown Name="upDown" Minimum="0" Maximum="10" Increment="0.5"
+        <Label Target="upDown" FontSize="14" FontWeight="Bold" VerticalAlignment="Center">Usage of decimal NumericUpDown:</Label>
-                     CultureInfo="en-US" VerticalAlignment="Center"
+        <NumericUpDown Name="upDown" Minimum="0" Maximum="10" Increment="0.5"
-                     Watermark="Enter text" FormatString="{Binding SelectedFormat.Value}"/>
+                       CultureInfo="en-US" VerticalAlignment="Center" Value="{Binding DecimalValue}"
+                       Watermark="Enter text" FormatString="{Binding SelectedFormat.Value}"/>
+      </StackPanel>
+
+      <StackPanel Orientation="Vertical" Margin="10">
+        <Label Target="DoubleUpDown" FontSize="14" FontWeight="Bold" VerticalAlignment="Center">Usage of double NumericUpDown:</Label>
+        <NumericUpDown Name="DoubleUpDown" Minimum="0" Maximum="10" Increment="0.5"
+                       CultureInfo="en-US" VerticalAlignment="Center" Value="{Binding DoubleValue}"
+                       Watermark="Enter text" FormatString="{Binding SelectedFormat.Value}"/>
+      </StackPanel>
       
-      <TextBlock FontSize="14" FontWeight="Bold" VerticalAlignment="Center">NumericUpDown with Validation Errors:</TextBlock>
+      <StackPanel Orientation="Vertical" Margin="10">
-      <NumericUpDown Minimum="0" Maximum="10" Increment="0.5"
+        <Label Target="ValidationUpDown" FontSize="14" FontWeight="Bold" VerticalAlignment="Center">NumericUpDown with Validation Errors:</Label>
-                     CultureInfo="en-US" VerticalAlignment="Center"
+        <NumericUpDown x:Name="ValidationUpDown" Minimum="0" Maximum="10" Increment="0.5"
-                     Watermark="Enter text" FormatString="{Binding SelectedFormat.Value}">
+                       CultureInfo="en-US" VerticalAlignment="Center"
-        <DataValidationErrors.Error>
+                       Watermark="Enter text" FormatString="{Binding SelectedFormat.Value}">
-          <sys:Exception /> 
+          <DataValidationErrors.Error>
-        </DataValidationErrors.Error>
+            <sys:Exception /> 
-      </NumericUpDown>
+          </DataValidationErrors.Error>
-    </StackPanel>
+        </NumericUpDown>
+      </StackPanel>
+    </WrapPanel>
 
   </StackPanel>
 </UserControl>

samples/ControlCatalog/Pages/NumericUpDownPage.xaml.cs

@@ -32,11 +32,26 @@ namespace ControlCatalog.Pages
         private FormatObject _selectedFormat;
         private IList<Location> _spinnerLocations;
 
+        private double _doubleValue;
+        private decimal _decimalValue;
+
         public NumbersPageViewModel()
         {
             SelectedFormat = Formats.FirstOrDefault();
         }
 
+        public double DoubleValue
+        {
+            get { return _doubleValue; }
+            set { this.RaiseAndSetIfChanged(ref _doubleValue, value); }
+        }
+
+        public decimal DecimalValue
+        {
+            get { return _decimalValue; }
+            set { this.RaiseAndSetIfChanged(ref _decimalValue, value); }
+        }
+
         public IList<FormatObject> Formats
         {
             get

samples/ControlCatalog/Pages/TextBoxPage.xaml

@@ -18,6 +18,7 @@
                  Watermark="Floating Watermark"
                  UseFloatingWatermark="True"
                  Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit."/>
+        <MaskedTextBox Width="200" ResetOnSpace="False"  Mask="(LLL) 999-0000"/>
         
         <TextBox Width="200" Text="Validation Error">
           <DataValidationErrors.Error>

samples/ControlCatalog/SideBar.xaml

@@ -16,7 +16,6 @@
         <Setter Property="Template">
             <ControlTemplate>
                 <Border 
-                    Margin="{TemplateBinding Margin}"
                     BorderBrush="{TemplateBinding BorderBrush}"
                     BorderThickness="{TemplateBinding BorderThickness}">
                     <DockPanel>

samples/ControlCatalog/ViewModels/ContextFlyoutPageViewModel.cs

@@ -1,78 +0,0 @@
-using System.Collections.Generic;
-using System.Reactive;
-using System.Threading.Tasks;
-using Avalonia.Controls;
-using Avalonia.VisualTree;
-using MiniMvvm;
-
-namespace ControlCatalog.ViewModels
-{
-    public class ContextFlyoutPageViewModel
-    {
-        public Control View { get; set; }
-        public ContextFlyoutPageViewModel()
-        {
-            OpenCommand = MiniCommand.CreateFromTask(Open);
-            SaveCommand = MiniCommand.Create(Save);
-            OpenRecentCommand = MiniCommand.Create<string>(OpenRecent);
-
-            MenuItems = new[]
-            {
-                new MenuItemViewModel { Header = "_Open...", Command = OpenCommand },
-                new MenuItemViewModel { Header = "Save", Command = SaveCommand },
-                new MenuItemViewModel { Header = "-" },
-                new MenuItemViewModel
-                {
-                    Header = "Recent",
-                    Items = new[]
-                    {
-                        new MenuItemViewModel
-                        {
-                            Header = "File1.txt",
-                            Command = OpenRecentCommand,
-                            CommandParameter = @"c:\foo\File1.txt"
-                        },
-                        new MenuItemViewModel
-                        {
-                            Header = "File2.txt",
-                            Command = OpenRecentCommand,
-                            CommandParameter = @"c:\foo\File2.txt"
-                        },
-                    }
-                },
-            };
-        }
-
-        public IReadOnlyList<MenuItemViewModel> MenuItems { get; set; }
-        public MiniCommand OpenCommand { get; }
-        public MiniCommand SaveCommand { get; }
-        public MiniCommand OpenRecentCommand { get; }
-
-        public async Task Open()
-        {
-            var window = View?.GetVisualRoot() as Window;
-            if (window == null)
-                return;
-            var dialog = new OpenFileDialog();
-            var result = await dialog.ShowAsync(window);
-
-            if (result != null)
-            {
-                foreach (var path in result)
-                {
-                    System.Diagnostics.Debug.WriteLine($"Opened: {path}");
-                }
-            }
-        }
-
-        public void Save()
-        {
-            System.Diagnostics.Debug.WriteLine("Save");
-        }
-
-        public void OpenRecent(string path)
-        {
-            System.Diagnostics.Debug.WriteLine($"Open recent: {path}");
-        }
-    }
-}

samples/ControlCatalog/ViewModels/ContextMenuPageViewModel.cs → samples/ControlCatalog/ViewModels/ContextPageViewModel.cs

@@ -7,10 +7,10 @@ using MiniMvvm;
 
 namespace ControlCatalog.ViewModels
 {
-    public class ContextMenuPageViewModel
+    public class ContextPageViewModel
     {
         public Control View { get; set; }
-        public ContextMenuPageViewModel()
+        public ContextPageViewModel()
         {
             OpenCommand = MiniCommand.CreateFromTask(Open);
             SaveCommand = MiniCommand.Create(Save);

samples/RenderDemo/MainWindow.xaml

@@ -36,6 +36,9 @@
       <TabItem Header="Transitions">
         <pages:TransitionsPage/>
       </TabItem>
+      <TabItem Header="Custom Animator">
+        <pages:CustomAnimatorPage/>
+      </TabItem>
       <TabItem Header="Clipping">
         <pages:ClippingPage/>
       </TabItem>

samples/RenderDemo/Pages/AnimationsPage.xaml

@@ -161,6 +161,151 @@
           </Animation>
         </Style.Animations>
       </Style>
+
+      <Style Selector="Border.Rect7">
+        <Style.Animations>
+          <Animation Duration="0:0:3"
+                     IterationCount="Infinite"
+                     PlaybackDirection="Alternate">
+            <KeyFrame Cue="0%">
+              <Setter Property="Background" Value="Red" />
+            </KeyFrame>
+            <KeyFrame Cue="30%">
+              <Setter Property="Background">
+                <LinearGradientBrush StartPoint="0%,0%" EndPoint="0%,100%">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </LinearGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="60%">
+              <Setter Property="Background" Value="Blue" />
+            </KeyFrame>
+            <KeyFrame Cue="100%">
+              <Setter Property="Background">
+                <LinearGradientBrush StartPoint="0%,0%" EndPoint="0%,100%">
+                  <GradientStop Offset="0" Color="Green"/>
+                  <GradientStop Offset="1" Color="Yellow"/>
+                </LinearGradientBrush>
+              </Setter>
+            </KeyFrame>
+          </Animation>
+        </Style.Animations>
+      </Style>
+
+      <Style Selector="Border.Rect8">
+        <Style.Animations>
+          <Animation Duration="0:0:3"
+                     IterationCount="Infinite"
+                     PlaybackDirection="Alternate">
+            <KeyFrame Cue="0%">
+              <Setter Property="Background">
+                <LinearGradientBrush StartPoint="0%,0%" EndPoint="0%,100%">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </LinearGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="50%">
+              <Setter Property="Background">
+                <LinearGradientBrush StartPoint="100%,0%" EndPoint="0%,100%">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="0.25" Color="Blue"/>
+                  <GradientStop Offset="0.5" Color="Blue"/>
+                  <GradientStop Offset="0.75" Color="Green"/>
+                  <GradientStop Offset="1" Color="Yellow"/>
+                </LinearGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="100%">
+              <Setter Property="Background">
+                <LinearGradientBrush StartPoint="0%,0%" EndPoint="0%,100%">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </LinearGradientBrush>
+              </Setter>
+            </KeyFrame>
+          </Animation>
+        </Style.Animations>
+      </Style>
+
+      <Style Selector="Border.Rect9">
+        <Style.Animations>
+          <Animation Duration="0:0:3"
+                     IterationCount="Infinite"
+                     PlaybackDirection="Alternate">
+            <KeyFrame Cue="0%">
+              <Setter Property="Background">
+                <ConicGradientBrush Center="50%,50%" Angle="0">
+                  <GradientStop Offset="0" Color="Blue"/>
+                  <GradientStop Offset="0.5" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </ConicGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="100%">
+              <Setter Property="Background">
+                <ConicGradientBrush Center="50%,70%" Angle="90">
+                  <GradientStop Offset="0" Color="Green"/>
+                  <GradientStop Offset="0.25" Color="Yellow"/>
+                  <GradientStop Offset="0.5" Color="Red"/>
+                  <GradientStop Offset="0.75" Color="Blue"/>
+                  <GradientStop Offset="1" Color="Green"/>
+                </ConicGradientBrush>
+              </Setter>
+            </KeyFrame>
+          </Animation>
+        </Style.Animations>
+      </Style>
+
+      <Style Selector="Border.Rect10">
+        <Style.Animations>
+          <Animation Duration="0:0:3"
+                     IterationCount="Infinite"
+                     PlaybackDirection="Normal">
+            <KeyFrame Cue="0%">
+              <Setter Property="Background">
+                <RadialGradientBrush Center="0%,100%" Radius="0.8">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </RadialGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="25%">
+              <Setter Property="Background">
+                <RadialGradientBrush Center="0%,0%" Radius="1">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </RadialGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="50%">
+              <Setter Property="Background">
+                <RadialGradientBrush Center="100%,0%" Radius="0.8">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </RadialGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="75%">
+              <Setter Property="Background">
+                <RadialGradientBrush Center="100%,100%" Radius="1">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </RadialGradientBrush>
+              </Setter>
+            </KeyFrame>
+            <KeyFrame Cue="100%">
+              <Setter Property="Background">
+                <RadialGradientBrush Center="0%,100%" Radius="0.8">
+                  <GradientStop Offset="0" Color="Red"/>
+                  <GradientStop Offset="1" Color="Blue"/>
+                </RadialGradientBrush>
+              </Setter>
+            </KeyFrame>
+          </Animation>
+        </Style.Animations>
+      </Style>
     </Styles>
   </UserControl.Styles>
   <Grid>
@@ -181,6 +326,10 @@
         <Border Classes="Test Rect6" Background="Red"/>
         <Border Classes="Test Shadow" CornerRadius="10" Child="{x:Null}" />
         <Border Classes="Test Shadow" CornerRadius="0 30 60 0" Child="{x:Null}" />
+        <Border Classes="Test Rect7" Child="{x:Null}" />
+        <Border Classes="Test Rect8" Child="{x:Null}" />
+        <Border Classes="Test Rect9" Child="{x:Null}" />
+        <Border Classes="Test Rect10" Child="{x:Null}" />
       </WrapPanel>
     </StackPanel>
   </Grid>

samples/RenderDemo/Pages/CustomAnimatorPage.xaml

@@ -0,0 +1,25 @@
+<UserControl 
+  xmlns="https://github.com/avaloniaui" 
+  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
+  xmlns:pages="clr-namespace:RenderDemo.Pages"
+  x:Class="RenderDemo.Pages.CustomAnimatorPage"
+  MaxWidth="600">
+  <Grid>
+    <TextBlock HorizontalAlignment="Center" VerticalAlignment="Center">
+      <TextBlock.Styles>
+        <Style Selector="TextBlock">
+          <Style.Animations>
+            <Animation Duration="0:0:1" IterationCount="Infinite">
+              <KeyFrame Cue="0%">
+                <Setter Property="Text" Value="" Animation.Animator="{x:Type pages:CustomStringAnimator}"/>
+              </KeyFrame>
+              <KeyFrame Cue="100%">
+                <Setter Property="Text" Value="0123456789" Animation.Animator="{x:Type pages:CustomStringAnimator}"/>
+              </KeyFrame>
+            </Animation>
+          </Style.Animations>
+        </Style>
+      </TextBlock.Styles>
+    </TextBlock>
+  </Grid>
+</UserControl>

samples/RenderDemo/Pages/CustomAnimatorPage.xaml.cs

@@ -0,0 +1,27 @@
+using System.Reactive.Linq;
+using Avalonia;
+using Avalonia.Animation;
+using Avalonia.Controls;
+using Avalonia.Controls.Shapes;
+using Avalonia.Data;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Markup.Xaml;
+using Avalonia.Media;
+using RenderDemo.ViewModels;
+
+namespace RenderDemo.Pages
+{
+    public class CustomAnimatorPage : UserControl
+    {
+        public CustomAnimatorPage()
+        {
+            InitializeComponent();
+        }
+
+        private void InitializeComponent()
+        {
+            AvaloniaXamlLoader.Load(this);
+        }
+    }
+}

samples/RenderDemo/Pages/CustomStringAnimator.cs

@@ -0,0 +1,16 @@
+using Avalonia.Animation.Animators;
+
+namespace RenderDemo.Pages
+{
+    public class CustomStringAnimator : Animator<string>
+    {
+        public override string Interpolate(double progress, string oldValue, string newValue)
+        {
+            if (newValue.Length == 0) return "";
+            var step = 1.0 / newValue.Length;
+            var length = (int)(progress / step);
+            var result = newValue.Substring(0, length + 1);
+            return result;
+        }
+    }
+}

samples/RenderDemo/Pages/TransitionsPage.xaml

@@ -141,6 +141,106 @@
       <Style Selector="Border.Shadow:pointerover">
         <Setter Property="BoxShadow" Value="inset 30 30 20 30 Green, 20 40 20 10 Red"/>
       </Style>
+
+      <Style Selector="Border.Rect10">
+        <Setter Property="Transitions">
+          <Transitions>
+            <BrushTransition Property="Background" Duration="0:0:0.5" />
+          </Transitions>
+        </Setter>
+        <Setter Property="Background" Value="Red" />
+      </Style>
+
+      <Style Selector="Border.Rect10:pointerover">
+        <Setter Property="Background" Value="Orange" />
+      </Style>
+
+      <Style Selector="Border.Rect11">
+        <Setter Property="Transitions">
+          <Transitions>
+            <BrushTransition Property="Background" Duration="0:0:0.5" />
+          </Transitions>
+        </Setter>
+        <Setter Property="Background" Value="Red" />
+      </Style>
+
+      <Style Selector="Border.Rect11:pointerover">
+        <Setter Property="Background" >
+          <LinearGradientBrush StartPoint="0%,0%" EndPoint="100%,100%">
+            <GradientStop Offset="0" Color="Red"/>
+            <GradientStop Offset="1" Color="Blue"/>
+          </LinearGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect12">
+        <Setter Property="Transitions">
+          <Transitions>
+            <BrushTransition Property="Background" Duration="0:0:0.5" />
+          </Transitions>
+        </Setter>
+        <Setter Property="Background" >
+          <LinearGradientBrush StartPoint="0%,0%" EndPoint="100%,100%">
+            <GradientStop Offset="0" Color="Red"/>
+            <GradientStop Offset="1" Color="Blue"/>
+          </LinearGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect12:pointerover">
+        <Setter Property="Background" >
+          <LinearGradientBrush StartPoint="100%,0%" EndPoint="0%,100%">
+            <GradientStop Offset="0" Color="Green"/>
+            <GradientStop Offset="1" Color="Yellow"/>
+          </LinearGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect13">
+        <Setter Property="Transitions">
+          <Transitions>
+            <BrushTransition Property="Background" Duration="0:0:0.5" />
+          </Transitions>
+        </Setter>
+        <Setter Property="Background" >
+          <ConicGradientBrush Center="50%,50%" Angle="0">
+            <GradientStop Offset="0" Color="Red"/>
+            <GradientStop Offset="1" Color="Blue"/>
+          </ConicGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect13:pointerover">
+        <Setter Property="Background" >
+          <ConicGradientBrush Center="70%,70%" Angle="90">
+            <GradientStop Offset="0" Color="Green"/>
+            <GradientStop Offset="1" Color="Yellow"/>
+          </ConicGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect14">
+        <Setter Property="Transitions">
+          <Transitions>
+            <BrushTransition Property="Background" Duration="0:0:0.5" />
+          </Transitions>
+        </Setter>
+        <Setter Property="Background" >
+          <RadialGradientBrush Center="50%,50%" Radius="0.5">
+            <GradientStop Offset="0" Color="Red"/>
+            <GradientStop Offset="1" Color="Blue"/>
+          </RadialGradientBrush>
+        </Setter>
+      </Style>
+
+      <Style Selector="Border.Rect14:pointerover">
+        <Setter Property="Background" >
+          <RadialGradientBrush Center="30%,30%" Radius="0.2">
+            <GradientStop Offset="0" Color="Green"/>
+            <GradientStop Offset="1" Color="Yellow"/>
+          </RadialGradientBrush>
+        </Setter>
+      </Style>
     </Styles>
   </UserControl.Styles>
 
@@ -166,6 +266,18 @@
 
         <Border Classes="Test Shadow" CornerRadius="10" Child="{x:Null}" />
         <Border Classes="Test Shadow" CornerRadius="0 30 60 0" Child="{x:Null}" />
+
+        <Border Classes="Test Rect10" />
+        <Border Classes="Test Rect11" />
+
+        <Border Classes="Test Rect12" Child="{x:Null}"/>
+        <Border Classes="Test Rect13" Child="{x:Null}"/>
+        <Border Classes="Test Rect14" Child="{x:Null}"/>
+        
+        <Border Classes="Test Rect14" />
+        <Border Classes="Test Rect14" />
+        <Border Classes="Test Rect14" />
+        <Border Classes="Test Rect14" />
       </WrapPanel>
     </StackPanel>
   </Grid>

samples/RenderDemo/SideBar.xaml

@@ -7,7 +7,6 @@
     <Setter Property="Template">
       <ControlTemplate>
         <Border
-            Margin="{TemplateBinding Margin}"
             BorderBrush="{TemplateBinding BorderBrush}"
             BorderThickness="{TemplateBinding BorderThickness}">
           <DockPanel>

samples/Sandbox/Program.cs

@@ -4,12 +4,12 @@ namespace Sandbox
 {
     public class Program
     {
-        static void Main(string[] args)
+        static void Main(string[] args) => BuildAvaloniaApp()
-        {
+            .StartWithClassicDesktopLifetime(args);
+
+        public static AppBuilder BuildAvaloniaApp() =>
             AppBuilder.Configure<App>()
                 .UsePlatformDetect()
-                .LogToTrace()
+                .LogToTrace();
-                .StartWithClassicDesktopLifetime(args);
-        }
     }
 }

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

@@ -55,6 +55,8 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         public virtual Size ClientSize => Size.ToSize(RenderScaling);
 
+        public Size? FrameSize => null;
+
         public IMouseDevice MouseDevice { get; } = new MouseDevice();
 
         public Action Closed { get; set; }
@@ -65,7 +67,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         public Action<Rect> Paint { get; set; }
 
-        public Action<Size> Resized { get; set; }
+        public Action<Size, PlatformResizeReason> Resized { get; set; }
 
         public Action<double> ScalingChanged { get; set; }
 
@@ -132,7 +134,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         protected virtual void OnResized(Size size)
         {
-            Resized?.Invoke(size);
+            Resized?.Invoke(size, PlatformResizeReason.Unspecified);
         }
 
         class ViewImpl : InvalidationAwareSurfaceView, ISurfaceHolderCallback, IInitEditorInfo

src/Avalonia.Animation/Animation.cs

@@ -3,10 +3,11 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
+using System.Threading;
 using System.Threading.Tasks;
+
 using Avalonia.Animation.Animators;
 using Avalonia.Animation.Easings;
-using Avalonia.Collections;
 using Avalonia.Data;
 using Avalonia.Metadata;
 
@@ -194,6 +195,33 @@ namespace Avalonia.Animation
         [Content]
         public KeyFrames Children { get; } = new KeyFrames();
 
+        // Store values for the Animator attached properties for IAnimationSetter objects.
+        private static readonly Dictionary<IAnimationSetter, Type> s_animators = new Dictionary<IAnimationSetter, Type>();
+
+        /// <summary>
+        /// Gets the value of the Animator attached property for a setter.
+        /// </summary>
+        /// <param name="setter">The animation setter.</param>
+        /// <returns>The property animator type.</returns>
+        public static Type GetAnimator(IAnimationSetter setter)
+        {
+            if (s_animators.TryGetValue(setter, out var type))
+            {
+                return type;
+            }
+            return null;
+        }
+
+        /// <summary>
+        /// Sets the value of the Animator attached property for a setter.
+        /// </summary>
+        /// <param name="setter">The animation setter.</param>
+        /// <param name="value">The property animator value.</param>
+        public static void SetAnimator(IAnimationSetter setter, Type value)
+        {
+            s_animators[setter] = value;
+        }
+
         private readonly static List<(Func<AvaloniaProperty, bool> Condition, Type Animator)> Animators = new List<(Func<AvaloniaProperty, bool>, Type)>
         {
             ( prop => typeof(bool).IsAssignableFrom(prop.PropertyType), typeof(BoolAnimator) ),
@@ -248,7 +276,7 @@ namespace Avalonia.Animation
             {
                 foreach (var setter in keyframe.Setters)
                 {
-                    var handler = GetAnimatorType(setter.Property);
+                    var handler = Animation.GetAnimator(setter) ?? GetAnimatorType(setter.Property);
 
                     if (handler == null)
                     {
@@ -292,7 +320,7 @@ namespace Avalonia.Animation
             return (newAnimatorInstances, subscriptions);
         }
 
-        /// <inheritdocs/>
+        /// <inheritdoc/>
         public IDisposable Apply(Animatable control, IClock clock, IObservable<bool> match, Action onComplete)
         {
             var (animators, subscriptions) = InterpretKeyframes(control);
@@ -317,25 +345,40 @@ namespace Avalonia.Animation
 
                 if (onComplete != null)
                 {
-                    Task.WhenAll(completionTasks).ContinueWith(_ => onComplete());
+                    Task.WhenAll(completionTasks).ContinueWith(
+                        (_, state) => ((Action)state).Invoke(),
+                        onComplete);
                 }
             }
             return new CompositeDisposable(subscriptions);
         }
 
-        /// <inheritdocs/>
+        /// <inheritdoc/>
-        public Task RunAsync(Animatable control, IClock clock = null)
+        public Task RunAsync(Animatable control, IClock clock = null, CancellationToken cancellationToken = default)
         {
+            if (cancellationToken.IsCancellationRequested)
+            {
+                return Task.CompletedTask;
+            }
+
             var run = new TaskCompletionSource<object>();
 
             if (this.IterationCount == IterationCount.Infinite)
                 run.SetException(new InvalidOperationException("Looping animations must not use the Run method."));
 
-            IDisposable subscriptions = null;
+            IDisposable subscriptions = null, cancellation = null;
             subscriptions = this.Apply(control, clock, Observable.Return(true), () =>
             {
-                run.SetResult(null);
+                run.TrySetResult(null);
+                subscriptions?.Dispose();
+                cancellation?.Dispose();
+            });
+
+            cancellation = cancellationToken.Register(() =>
+            {
+                run.TrySetResult(null);
                 subscriptions?.Dispose();
+                cancellation?.Dispose();
             });
 
             return run.Task;

src/Avalonia.Animation/AnimationInstance`1.cs

@@ -5,6 +5,7 @@ using Avalonia.Animation.Animators;
 using Avalonia.Animation.Utils;
 using Avalonia.Data;
 using Avalonia.Reactive;
+using JetBrains.Annotations;
 
 namespace Avalonia.Animation
 {
@@ -36,6 +37,7 @@ namespace Avalonia.Animation
         private IDisposable _timerSub;
         private readonly IClock _baseClock;
         private IClock _clock;
+        private EventHandler<AvaloniaPropertyChangedEventArgs> _propertyChangedDelegate;
 
         public AnimationInstance(Animation animation, Animatable control, Animator<T> animator, IClock baseClock, Action OnComplete, Func<double, T, T> Interpolator)
         {
@@ -45,8 +47,6 @@ namespace Avalonia.Animation
             _onCompleteAction = OnComplete;
             _interpolator = Interpolator;
             _baseClock = baseClock;
-            _neutralValue = (T)_targetControl.GetValue(_animator.Property);
-
             FetchProperties();
         }
 
@@ -80,6 +80,7 @@ namespace Avalonia.Animation
             // Animation may have been stopped before it has finished.
             ApplyFinalFill();
 
+            _targetControl.PropertyChanged -= _propertyChangedDelegate;
             _timerSub?.Dispose();
             _clock.PlayState = PlayState.Stop;
         }
@@ -88,6 +89,9 @@ namespace Avalonia.Animation
         {
             _clock = new Clock(_baseClock);
             _timerSub = _clock.Subscribe(Step);
+            _propertyChangedDelegate ??= ControlPropertyChanged;
+            _targetControl.PropertyChanged += _propertyChangedDelegate;
+            UpdateNeutralValue();
         }
 
         public void Step(TimeSpan frameTick)
@@ -216,5 +220,22 @@ namespace Avalonia.Animation
                 }
             }
         }
+
+        private void UpdateNeutralValue()
+        {
+            var property = _animator.Property;
+            var baseValue = _targetControl.GetBaseValue(property, BindingPriority.LocalValue);
+
+            _neutralValue = baseValue != AvaloniaProperty.UnsetValue ?
+                (T)baseValue : (T)_targetControl.GetValue(property);
+        }
+
+        private void ControlPropertyChanged(object sender, AvaloniaPropertyChangedEventArgs e)
+        {
+            if (e.Property == _animator.Property && e.Priority > BindingPriority.Animation)
+            {
+                UpdateNeutralValue();
+            }
+        }
     }
 }

src/Avalonia.Animation/ApiCompatBaseline.txt

@@ -0,0 +1,6 @@
+Compat issues with assembly Avalonia.Animation:
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.Animation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Threading.Tasks.Task Avalonia.Animation.IAnimation.RunAsync(Avalonia.Animation.Animatable, Avalonia.Animation.IClock, System.Threading.CancellationToken)' is present in the implementation but not in the contract.
+Total Issues: 4

src/Avalonia.Animation/IAnimation.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Avalonia.Animation
@@ -16,6 +17,6 @@ namespace Avalonia.Animation
         /// <summary>
         /// Run the animation on the specified control.
         /// </summary>
-        Task RunAsync(Animatable control, IClock clock);
+        Task RunAsync(Animatable control, IClock clock, CancellationToken cancellationToken = default);
     }
 }

src/Avalonia.Base/AvaloniaObject.cs

@@ -861,7 +861,7 @@ namespace Avalonia
         }
 
         /// <summary>
-        /// Logs a mesage if the notification represents a binding error.
+        /// Logs a message if the notification represents a binding error.
         /// </summary>
         /// <param name="property">The property being bound.</param>
         /// <param name="value">The binding notification.</param>

src/Avalonia.Base/AvaloniaObjectExtensions.cs

@@ -585,6 +585,30 @@ namespace Avalonia
             });
         }
 
+        /// <summary>
+        /// Subscribes to a property changed notifications for changes that originate from a
+        /// <typeparamref name="TTarget"/>.
+        /// </summary>
+        /// <typeparam name="TTarget">The type of the property change sender.</typeparam>
+        /// /// <typeparam name="TValue">The type of the property..</typeparam>
+        /// <param name="observable">The property changed observable.</param>
+        /// <param name="action">
+        /// The method to call. The parameters are the sender and the event args.
+        /// </param>
+        /// <returns>A disposable that can be used to terminate the subscription.</returns>
+        public static IDisposable AddClassHandler<TTarget, TValue>(
+            this IObservable<AvaloniaPropertyChangedEventArgs<TValue>> observable,
+            Action<TTarget, AvaloniaPropertyChangedEventArgs<TValue>> action) where TTarget : AvaloniaObject
+        {
+            return observable.Subscribe(e =>
+            {
+                if (e.Sender is TTarget target)
+                {
+                    action(target, e);
+                }
+            });
+        }
+
         /// <summary>
         /// Subscribes to a property changed notifications for changes that originate from a
         /// <typeparamref name="TTarget"/>.

src/Avalonia.Base/AvaloniaProperty.cs

@@ -465,9 +465,9 @@ namespace Avalonia
         /// Uses the visitor pattern to resolve an untyped property to a typed property.
         /// </summary>
         /// <typeparam name="TData">The type of user data passed.</typeparam>
-        /// <param name="vistor">The visitor which will accept the typed property.</param>
+        /// <param name="visitor">The visitor which will accept the typed property.</param>
         /// <param name="data">The user data to pass.</param>
-        public abstract void Accept<TData>(IAvaloniaPropertyVisitor<TData> vistor, ref TData data)
+        public abstract void Accept<TData>(IAvaloniaPropertyVisitor<TData> visitor, ref TData data)
             where TData : struct;
 
         /// <summary>

src/Avalonia.Base/AvaloniaPropertyChangedEventArgs.cs

@@ -58,8 +58,8 @@ namespace Avalonia
         /// <remarks>
         /// This will usually be true, except in
         /// <see cref="AvaloniaObject.OnPropertyChangedCore{T}(AvaloniaPropertyChangedEventArgs{T})"/>
-        /// which recieves notifications for all changes to property values, whether a value with a higher
+        /// which receives notifications for all changes to property values, whether a value with a higher
-        /// priority is present or not. When this property is false, the change that is being signalled
+        /// priority is present or not. When this property is false, the change that is being signaled
         /// has not resulted in a change to the property value on the object.
         /// </remarks>
         public bool IsEffectiveValueChange { get; private set; }

src/Avalonia.Base/Collections/AvaloniaList.cs

@@ -280,8 +280,8 @@ namespace Avalonia.Collections
         /// <summary>
         /// Gets a range of items from the collection.
         /// </summary>
-        /// <param name="index">The first index to remove.</param>
+        /// <param name="index">The zero-based <see cref="AvaloniaList{T}"/> index at which the range starts.</param>
-        /// <param name="count">The number of items to remove.</param>
+        /// <param name="count">The number of elements in the range.</param>
         public IEnumerable<T> GetRange(int index, int count)
         {
             return _inner.GetRange(index, count);
@@ -454,6 +454,28 @@ namespace Avalonia.Collections
             }
         }
 
+        /// <summary>
+        /// Ensures that the capacity of the list is at least <see cref="Capacity"/>.
+        /// </summary>
+        /// <param name="capacity">The capacity.</param>
+        public void EnsureCapacity(int capacity)
+        {
+            // Adapted from List<T> implementation.
+            var currentCapacity = _inner.Capacity;
+
+            if (currentCapacity < capacity)
+            {
+                var newCapacity = currentCapacity == 0 ? 4 : currentCapacity * 2;
+
+                if (newCapacity < capacity)
+                {
+                    newCapacity = capacity;
+                }
+
+                _inner.Capacity = newCapacity;
+            }
+        }
+
         /// <summary>
         /// Removes an item from the collection.
         /// </summary>
@@ -633,24 +655,6 @@ namespace Avalonia.Collections
         /// <inheritdoc/>
         Delegate[] INotifyCollectionChangedDebug.GetCollectionChangedSubscribers() => _collectionChanged?.GetInvocationList();
 
-        private void EnsureCapacity(int capacity)
-        {
-            // Adapted from List<T> implementation.
-            var currentCapacity = _inner.Capacity;
-
-            if (currentCapacity < capacity)
-            {
-                var newCapacity = currentCapacity == 0 ? 4 : currentCapacity * 2;
-
-                if (newCapacity < capacity)
-                {
-                    newCapacity = capacity;
-                }
-
-                _inner.Capacity = newCapacity;
-            }
-        }
-
         /// <summary>
         /// Raises the <see cref="CollectionChanged"/> event with an add action.
         /// </summary>

src/Avalonia.Base/Collections/Pooled/PooledList.cs

@@ -1271,7 +1271,7 @@ namespace Avalonia.Collections.Pooled
         /// Reverses the elements in a range of this list. Following a call to this
         /// method, an element in the range given by index and count
         /// which was previously located at index i will now be located at
-        /// index index + (index + count - i - 1).
+        /// index + (index + count - i - 1).
         /// </summary>
         public void Reverse(int index, int count)
         {

src/Avalonia.Base/Data/Converters/BoolConverters.cs

@@ -18,5 +18,11 @@ namespace Avalonia.Data.Converters
         /// </summary>
         public static readonly IMultiValueConverter Or =
             new FuncMultiValueConverter<bool, bool>(x => x.Any(y => y));
+
+        /// <summary>
+        /// A value converter that returns true when input is false and false when input is true.
+        /// </summary>
+        public static readonly IValueConverter Not =
+            new FuncValueConverter<bool, bool>(x => !x);
     }
 }

src/Avalonia.Base/Data/Converters/FuncValueConverter.cs

@@ -26,7 +26,7 @@ namespace Avalonia.Data.Converters
         /// <inheritdoc/>
         public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
         {
-            if (value is TIn || (value == null && TypeUtilities.AcceptsNull(typeof(TIn))))
+            if (TypeUtilities.CanCast<TIn>(value))
             {
                 return _convert((TIn)value);
             }

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

@@ -20,7 +20,7 @@ namespace Avalonia.Data.Core.Plugins
         /// </summary>
         /// <param name="reference">A weak reference to the object.</param>
         /// <param name="propertyName">The property name.</param>
-        /// <param name="inner">The inner property accessor used to aceess the property.</param>
+        /// <param name="inner">The inner property accessor used to access the property.</param>
         /// <returns>
         /// An <see cref="IPropertyAccessor"/> interface through which future interactions with the 
         /// property will be made.

src/Avalonia.Base/DirectPropertyBase.cs

@@ -13,7 +13,7 @@ namespace Avalonia
     /// <typeparam name="TValue">The type of the property's value.</typeparam>
     /// <remarks>
     /// Whereas <see cref="DirectProperty{TOwner, TValue}"/> is typed on the owner type, this base
-    /// class provides a non-owner-typed interface to a direct poperty.
+    /// class provides a non-owner-typed interface to a direct property.
     /// </remarks>
     public abstract class DirectPropertyBase<TValue> : AvaloniaProperty<TValue>
     {
@@ -123,9 +123,9 @@ namespace Avalonia
         }
 
         /// <inheritdoc/>
-        public override void Accept<TData>(IAvaloniaPropertyVisitor<TData> vistor, ref TData data)
+        public override void Accept<TData>(IAvaloniaPropertyVisitor<TData> visitor, ref TData data)
         {
-            vistor.Visit(this, ref data);
+            visitor.Visit(this, ref data);
         }
 
         /// <inheritdoc/>

src/Avalonia.Base/DirectPropertyMetadata`1.cs

@@ -38,7 +38,7 @@ namespace Avalonia
         /// <remarks>
         /// Data validation is validation performed at the target of a binding, for example in a
         /// view model using the INotifyDataErrorInfo interface. Only certain properties on a
-        /// control (such as a TextBox's Text property) will be interested in recieving data
+        /// control (such as a TextBox's Text property) will be interested in receiving data
         /// validation messages so this feature must be explicitly enabled by setting this flag.
         /// </remarks>
         public bool? EnableDataValidation { get; private set; }

src/Avalonia.Base/Metadata/NullableAttributes.cs

@@ -1,6 +1,5 @@
 #pragma warning disable MA0048 // File name must match type name
 #define INTERNAL_NULLABLE_ATTRIBUTES
-#if NETSTANDARD2_0 ||  NETCOREAPP2_0 ||  NETCOREAPP2_1 ||  NETCOREAPP2_2 || NET45 || NET451 || NET452 || NET6 || NET461 || NET462 || NET47 || NET471 || NET472 || NET48
 
 // https://github.com/dotnet/corefx/blob/48363ac826ccf66fbe31a5dcb1dc2aab9a7dd768/src/Common/src/CoreLib/System/Diagnostics/CodeAnalysis/NullableAttributes.cs
 
@@ -10,6 +9,7 @@
 
 namespace System.Diagnostics.CodeAnalysis
 {
+#if NETSTANDARD2_0 || NETCOREAPP2_0 || NETCOREAPP2_1 || NETCOREAPP2_2 || NET45 || NET451 || NET452 || NET6 || NET461 || NET462 || NET47 || NET471 || NET472 || NET48
     /// <summary>Specifies that null is allowed as an input even if the corresponding type disallows it.</summary>
     [AttributeUsage(AttributeTargets.Field | AttributeTargets.Parameter | AttributeTargets.Property, Inherited = false)]
 #if INTERNAL_NULLABLE_ATTRIBUTES
@@ -136,5 +136,82 @@ namespace System.Diagnostics.CodeAnalysis
         /// <summary>Gets the condition parameter value.</summary>
         public bool ParameterValue { get; }
     }
-}
+#endif // NETSTANDARD2_0 attributes
+
+#if NETSTANDARD2_1 || NETSTANDARD2_0 || NETCOREAPP2_0 || NETCOREAPP2_1 || NETCOREAPP2_2 || NETCOREAPP3_1 || NET45 || NET451 || NET452 || NET6 || NET461 || NET462 || NET47 || NET471 || NET472 || NET48
+    /// <summary>
+    /// Specifies that the method or property will ensure that the listed field and property members have
+    /// not-<see langword="null"/> values.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+    public
 #endif
+    sealed class MemberNotNullAttribute : Attribute
+    {
+        /// <summary>Gets field or property member names.</summary>
+        public string[] Members { get; }
+
+        /// <summary>Initializes the attribute with a field or property member.</summary>
+        /// <param name="member">The field or property member that is promised to be not-null.</param>
+        public MemberNotNullAttribute(string member)
+        {
+            Members = new[] { member };
+        }
+
+        /// <summary>Initializes the attribute with the list of field and property members.</summary>
+        /// <param name="members">The list of field and property members that are promised to be not-null.</param>
+        public MemberNotNullAttribute(params string[] members)
+        {
+            Members = members;
+        }
+    }
+
+    /// <summary>
+    /// Specifies that the method or property will ensure that the listed field and property members have
+    /// non-<see langword="null"/> values when returning with the specified return value condition.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Method | AttributeTargets.Property, Inherited = false, AllowMultiple = true)]
+#if INTERNAL_NULLABLE_ATTRIBUTES
+    internal
+#else
+    public
+#endif
+    sealed class MemberNotNullWhenAttribute : Attribute
+    {
+        /// <summary>Gets the return value condition.</summary>
+        public bool ReturnValue { get; }
+
+        /// <summary>Gets field or property member names.</summary>
+        public string[] Members { get; }
+
+        /// <summary>Initializes the attribute with the specified return value condition and a field or property member.</summary>
+        /// <param name="returnValue">
+        /// The return value condition. If the method returns this value,
+        /// the associated parameter will not be <see langword="null"/>.
+        /// </param>
+        /// <param name="member">The field or property member that is promised to be not-<see langword="null"/>.</param>
+        public MemberNotNullWhenAttribute(bool returnValue, string member)
+        {
+            ReturnValue = returnValue;
+            Members = new[] { member };
+        }
+
+        /// <summary>Initializes the attribute with the specified return value condition and list of field and property members.
+        /// </summary>
+        /// <param name="returnValue">
+        /// The return value condition. If the method returns this value,
+        /// the associated parameter will not be <see langword="null"/>.
+        /// </param>
+        /// <param name="members">The list of field and property members that are promised to be not-null.</param>
+        public MemberNotNullWhenAttribute(bool returnValue, params string[] members)
+        {
+            ReturnValue = returnValue;
+            Members = members;
+        }
+    }
+#endif // NETSTANDARD2_1 attributes
+}
+

src/Avalonia.Base/Threading/AvaloniaSynchronizationContext.cs

@@ -39,7 +39,7 @@ namespace Avalonia.Threading
             if (Dispatcher.UIThread.CheckAccess())
                 d(state);
             else
-                Dispatcher.UIThread.InvokeAsync(() => d(state), DispatcherPriority.Send).Wait();
+                Dispatcher.UIThread.InvokeAsync(() => d(state), DispatcherPriority.Send).GetAwaiter().GetResult();
         }
 
 

src/Avalonia.Base/Utilities/MathUtilities.cs

@@ -224,6 +224,34 @@ namespace Avalonia.Utilities
             }
         }
 
+        /// <summary>
+        /// Clamps a value between a minimum and maximum value.
+        /// </summary>
+        /// <param name="val">The value.</param>
+        /// <param name="min">The minimum value.</param>
+        /// <param name="max">The maximum value.</param>
+        /// <returns>The clamped value.</returns>
+        public static decimal Clamp(decimal val, decimal min, decimal max)
+        {
+            if (min > max)
+            {
+                ThrowCannotBeGreaterThanException(min, max);
+            }
+
+            if (val < min)
+            {
+                return min;
+            }
+            else if (val > max)
+            {
+                return max;
+            }
+            else
+            {
+                return val;
+            }
+        }
+
         /// <summary>
         /// Clamps a value between a minimum and maximum value.
         /// </summary>
@@ -281,8 +309,8 @@ namespace Avalonia.Utilities
         {
             return angle * 2 * Math.PI;
         }
-        
+
-        private static void ThrowCannotBeGreaterThanException(double min, double max)
+        private static void ThrowCannotBeGreaterThanException<T>(T min, T max)
         {
             throw new ArgumentException($"{min} cannot be greater than {max}.");
         }

src/Avalonia.Base/Utilities/TypeUtilities.cs

@@ -3,6 +3,7 @@ using System.ComponentModel;
 using System.Globalization;
 using System.Linq;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 
 namespace Avalonia.Utilities
 {
@@ -93,13 +94,36 @@ namespace Avalonia.Utilities
             return !type.IsValueType || IsNullableType(type);
         }
 
+        /// <summary>
+        /// Returns a value indicating whether null can be assigned to the specified type.
+        /// </summary>
+        /// <typeparam name="T">The type</typeparam>
+        /// <returns>True if the type accepts null values; otherwise false.</returns>
+        [MethodImpl(MethodImplOptions.AggressiveInlining)]
+        public static bool AcceptsNull<T>()
+        {
+            return default(T) is null;
+        }
+
+        /// <summary>
+        /// Returns a value indicating whether value can be casted to the specified type.
+        /// If value is null, checks if instances of that type can be null.
+        /// </summary>
+        /// <typeparam name="T">The type to cast to</typeparam>
+        /// <param name="value">The value to check if cast possible</param>
+        /// <returns>True if the cast is possible, otherwise false.</returns>
+        public static bool CanCast<T>(object value)
+        {
+            return value is T || (value is null && AcceptsNull<T>());
+        }
+
         /// <summary>
         /// Try to convert a value to a type by any means possible.
         /// </summary>
-        /// <param name="to">The type to cast to.</param>
+        /// <param name="to">The type to convert to.</param>
-        /// <param name="value">The value to cast.</param>
+        /// <param name="value">The value to convert.</param>
         /// <param name="culture">The culture to use.</param>
-        /// <param name="result">If successful, contains the cast value.</param>
+        /// <param name="result">If successful, contains the convert value.</param>
         /// <returns>True if the cast was successful, otherwise false.</returns>
         public static bool TryConvert(Type to, object value, CultureInfo culture, out object result)
         {
@@ -216,10 +240,10 @@ namespace Avalonia.Utilities
         /// Try to convert a value to a type using the implicit conversions allowed by the C#
         /// language.
         /// </summary>
-        /// <param name="to">The type to cast to.</param>
+        /// <param name="to">The type to convert to.</param>
-        /// <param name="value">The value to cast.</param>
+        /// <param name="value">The value to convert.</param>
-        /// <param name="result">If successful, contains the cast value.</param>
+        /// <param name="result">If successful, contains the converted value.</param>
-        /// <returns>True if the cast was successful, otherwise false.</returns>
+        /// <returns>True if the convert was successful, otherwise false.</returns>
         public static bool TryConvertImplicit(Type to, object value, out object result)
         {
             if (value == null)
@@ -278,8 +302,8 @@ namespace Avalonia.Utilities
         /// Convert a value to a type by any means possible, returning the default for that type
         /// if the value could not be converted.
         /// </summary>
-        /// <param name="value">The value to cast.</param>
+        /// <param name="value">The value to convert.</param>
-        /// <param name="type">The type to cast to..</param>
+        /// <param name="type">The type to convert to..</param>
         /// <param name="culture">The culture to use.</param>
         /// <returns>A value of <paramref name="type"/>.</returns>
         public static object ConvertOrDefault(object value, Type type, CultureInfo culture)
@@ -291,8 +315,8 @@ namespace Avalonia.Utilities
         /// Convert a value to a type using the implicit conversions allowed by the C# language or
         /// return the default for the type if the value could not be converted.
         /// </summary>
-        /// <param name="value">The value to cast.</param>
+        /// <param name="value">The value to convert.</param>
-        /// <param name="type">The type to cast to..</param>
+        /// <param name="type">The type to convert to.</param>
         /// <returns>A value of <paramref name="type"/>.</returns>
         public static object ConvertImplicitOrDefault(object value, Type type)
         {

src/Avalonia.Controls.DataGrid/Collections/DataGridCollectionView.cs

@@ -877,7 +877,7 @@ namespace Avalonia.Collections
                         if (!CheckFlag(CollectionViewFlags.IsMoveToPageDeferred))
                         {
                             // if the temporaryGroup was not created yet and is out of sync
-                            // then create it so that we can use it as a refernce while paging.
+                            // then create it so that we can use it as a reference while paging.
                             if (IsGrouping && _temporaryGroup.ItemCount != InternalList.Count)
                             {
                                 PrepareTemporaryGroups();
@@ -889,7 +889,7 @@ namespace Avalonia.Collections
                     else if (IsGrouping)
                     {
                         // if the temporaryGroup was not created yet and is out of sync
-                        // then create it so that we can use it as a refernce while paging.
+                        // then create it so that we can use it as a reference while paging.
                         if (_temporaryGroup.ItemCount != InternalList.Count)
                         {
                             // update the groups that get created for the
@@ -1951,7 +1951,7 @@ namespace Avalonia.Collections
             EnsureCollectionInSync();
             VerifyRefreshNotDeferred();
 
-            // for indicies larger than the count
+            // for indices larger than the count
             if (index >= Count || index < 0)
             {
                 throw new ArgumentOutOfRangeException("index");
@@ -3800,7 +3800,7 @@ namespace Avalonia.Collections
         /// </summary>
         /// <remarks>
         /// This method can be called from a constructor - it does not call
-        /// any virtuals.  The 'count' parameter is substitute for the real Count,
+        /// any virtuals. The 'count' parameter is substitute for the real Count,
         /// used only when newItem is null.
         /// In that case, this method sets IsCurrentAfterLast to true if and only
         /// if newPosition >= count.  This distinguishes between a null belonging

src/Avalonia.Controls.DataGrid/Collections/DataGridGroupDescription.cs

@@ -83,8 +83,9 @@ namespace Avalonia.Collections
             if (key == null)
                 key = item;
 
-            if (_valueConverter != null)
+            var valueConverter = ValueConverter;
-                key = _valueConverter.Convert(key, typeof(object), level, culture);
+            if (valueConverter != null)
+                key = valueConverter.Convert(key, typeof(object), level, culture);
 
             return key;
         }
@@ -99,6 +100,8 @@ namespace Avalonia.Collections
         }
         public override string PropertyName => _propertyPath;
 
+        public IValueConverter ValueConverter { get => _valueConverter; set => _valueConverter = value; }
+
         private Type GetPropertyType(object o)
         {
             return o.GetType().GetNestedPropertyType(_propertyPath);

src/Avalonia.Controls.DataGrid/DataGrid.cs

@@ -25,6 +25,7 @@ using System.ComponentModel.DataAnnotations;
 using Avalonia.Controls.Utils;
 using Avalonia.Layout;
 using Avalonia.Controls.Metadata;
+using Avalonia.Input.GestureRecognizers;
 
 namespace Avalonia.Controls
 {
@@ -67,7 +68,7 @@ namespace Avalonia.Controls
         private const double DATAGRID_minimumColumnHeaderHeight = 4;
         internal const double DATAGRID_maximumStarColumnWidth = 10000;
         internal const double DATAGRID_minimumStarColumnWidth = 0.001;
-        private const double DATAGRID_mouseWheelDelta = 72.0;
+        private const double DATAGRID_mouseWheelDelta = 50.0;
         private const double DATAGRID_maxHeadersThickness = 32768;
 
         private const double DATAGRID_defaultRowHeight = 22;
@@ -75,7 +76,6 @@ namespace Avalonia.Controls
         private const double DATAGRID_defaultMinColumnWidth = 20;
         private const double DATAGRID_defaultMaxColumnWidth = double.PositiveInfinity;
 
-        private List<Exception> _validationErrors;
         private List<Exception> _bindingValidationErrors;
         private IDisposable _validationSubscription;
 
@@ -102,7 +102,6 @@ namespace Avalonia.Controls
         private bool _areHandlersSuspended;
         private bool _autoSizingColumns;
         private IndexToValueTable<bool> _collapsedSlotsTable;
-        private DataGridCellCoordinates _currentCellCoordinates;
         private Control _clickedElement;
 
         // used to store the current column during a Reset
@@ -141,7 +140,6 @@ namespace Avalonia.Controls
         private DataGridSelectedItemsCollection _selectedItems;
         private bool _temporarilyResetCurrentCell;
         private object _uneditedValue; // Represents the original current cell value at the time it enters editing mode.
-        private ICellEditBinding _currentCellEditBinding;
 
         // An approximation of the sum of the heights in pixels of the scrolling rows preceding
         // the first displayed scrolling row.  Since the scrolled off rows are discarded, the grid
@@ -2217,32 +2215,71 @@ namespace Avalonia.Controls
         /// <param name="e">PointerWheelEventArgs</param>
         protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
         {
-            if (IsEnabled && !e.Handled && DisplayData.NumDisplayedScrollingElements > 0)
+            e.Handled = e.Handled || UpdateScroll(e.Delta * DATAGRID_mouseWheelDelta);
+        }
+
+        internal bool UpdateScroll(Vector delta)
+        {
+            if (IsEnabled && DisplayData.NumDisplayedScrollingElements > 0)
             {
-                double scrollHeight = 0;
+                var handled = false;
-                if (e.Delta.Y > 0)
+                var scrollHeight = 0d;
+
+                // Vertical scroll handling
+                if (delta.Y > 0)
                 {
-                    scrollHeight = Math.Max(-_verticalOffset, -DATAGRID_mouseWheelDelta);
+                    scrollHeight = Math.Max(-_verticalOffset, -delta.Y);
                 }
-                else if (e.Delta.Y < 0)
+                else if (delta.Y < 0)
                 {
                     if (_vScrollBar != null && VerticalScrollBarVisibility == ScrollBarVisibility.Visible)
                     {
-                        scrollHeight = Math.Min(Math.Max(0, _vScrollBar.Maximum - _verticalOffset), DATAGRID_mouseWheelDelta);
+                        scrollHeight = Math.Min(Math.Max(0, _vScrollBar.Maximum - _verticalOffset), -delta.Y);
                     }
                     else
                     {
                         double maximum = EdgedRowsHeightCalculated - CellsHeight;
-                        scrollHeight = Math.Min(Math.Max(0, maximum - _verticalOffset), DATAGRID_mouseWheelDelta);
+                        scrollHeight = Math.Min(Math.Max(0, maximum - _verticalOffset), -delta.Y);
                     }
                 }
+
                 if (scrollHeight != 0)
                 {
                     DisplayData.PendingVerticalScrollHeight = scrollHeight;
+                    handled = true;
+                }
+
+                // Horizontal scroll handling
+                if (delta.X != 0)
+                {
+                    var originalHorizontalOffset = HorizontalOffset;
+                    var horizontalOffset = originalHorizontalOffset - delta.X;
+                    var widthNotVisible = Math.Max(0, ColumnsInternal.VisibleEdgedColumnsWidth - CellsWidth);
+
+                    if (horizontalOffset < 0)
+                    {
+                        horizontalOffset = 0;
+                    }
+                    if (horizontalOffset > widthNotVisible)
+                    {
+                        horizontalOffset = widthNotVisible;
+                    }
+
+                    if (horizontalOffset != originalHorizontalOffset)
+                    {
+                        HorizontalOffset = horizontalOffset;
+                        handled = true;
+                    }
+                }
+
+                if (handled)
+                {
                     InvalidateRowsMeasure(invalidateIndividualElements: false);
-                    e.Handled = true;
+                    return true;
                 }
             }
+
+            return false;
         }
 
         /// <summary>
@@ -3002,6 +3039,12 @@ namespace Avalonia.Controls
             }
         }
 
+        //TODO: Ensure right button is checked for
+        internal bool UpdateStateOnMouseRightButtonDown(PointerPressedEventArgs pointerPressedEventArgs, int columnIndex, int slot, bool allowEdit)
+        {
+            KeyboardHelper.GetMetaKeyState(pointerPressedEventArgs.KeyModifiers, out bool ctrl, out bool shift);
+            return UpdateStateOnMouseRightButtonDown(pointerPressedEventArgs, columnIndex, slot, allowEdit, shift, ctrl);
+        }
         //TODO: Ensure left button is checked for
         internal bool UpdateStateOnMouseLeftButtonDown(PointerPressedEventArgs pointerPressedEventArgs, int columnIndex, int slot, bool allowEdit)
         {
@@ -4452,17 +4495,27 @@ namespace Avalonia.Controls
                 element = dataGridColumn.GenerateEditingElementInternal(dataGridCell, dataGridRow.DataContext);
                 if (element != null)
                 {
-                    // Subscribe to the new element's events
+
-                    element.Initialized += EditingElement_Initialized;
+                    dataGridCell.Content = element;
+                    if (element.IsInitialized)
+                    {
+                        PreparingCellForEditPrivate(element as Control);
+                    }
+                    else
+                    {
+                        // Subscribe to the new element's events
+                        element.Initialized += EditingElement_Initialized;
+                    }
                 }
             }
             else
             {
                 // Generate Element and apply column style if available
                 element = dataGridColumn.GenerateElementInternal(dataGridCell, dataGridRow.DataContext);
+                dataGridCell.Content = element;
             }
 
-            dataGridCell.Content = element;
+            
         }
 
         private void PreparingCellForEditPrivate(Control editingElement)
@@ -5674,6 +5727,35 @@ namespace Avalonia.Controls
             VerticalScroll?.Invoke(sender, e);
         }
 
+        //TODO: Ensure right button is checked for
+        private bool UpdateStateOnMouseRightButtonDown(PointerPressedEventArgs pointerPressedEventArgs, int columnIndex, int slot, bool allowEdit, bool shift, bool ctrl)
+        {
+            Debug.Assert(slot >= 0);
+
+            if (shift || ctrl)
+            {
+                return true;
+            }
+            if (IsSlotOutOfBounds(slot))
+            {
+                return true;
+            }
+            if (GetRowSelection(slot))
+            {
+                return true;
+            }
+            // Unselect everything except the row that was clicked on
+            try
+            {
+                UpdateSelectionAndCurrency(columnIndex, slot, DataGridSelectionAction.SelectCurrent, scrollIntoView: false);
+            }
+            finally
+            {
+                NoSelectionChangeCount--;
+            }
+            return true;
+        }
+
         //TODO: Ensure left button is checked for
         private bool UpdateStateOnMouseLeftButtonDown(PointerPressedEventArgs pointerPressedEventArgs, int columnIndex, int slot, bool allowEdit, bool shift, bool ctrl)
         {
@@ -5734,7 +5816,7 @@ namespace Avalonia.Controls
                 {
                     if (SelectionMode == DataGridSelectionMode.Single || !ctrl)
                     {
-                        // Unselect the currectly selected rows except the new selected row
+                        // Unselect the currently selected rows except the new selected row
                         action = DataGridSelectionAction.SelectCurrent;
                     }
                     else

src/Avalonia.Controls.DataGrid/DataGridCell.cs

@@ -161,21 +161,42 @@ namespace Avalonia.Controls
         private void DataGridCell_PointerPressed(PointerPressedEventArgs e)
         {
             // OwningGrid is null for TopLeftHeaderCell and TopRightHeaderCell because they have no OwningRow
-            if (OwningGrid != null)
+            if (OwningGrid == null)
             {
-                OwningGrid.OnCellPointerPressed(new DataGridCellPointerPressedEventArgs(this, OwningRow, OwningColumn, e));
+                return;
-                if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+            }
+            OwningGrid.OnCellPointerPressed(new DataGridCellPointerPressedEventArgs(this, OwningRow, OwningColumn, e));
+            if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+            {
+                if (!e.Handled)
+                //if (!e.Handled && OwningGrid.IsTabStop)
                 {
-                    if (!e.Handled)
+                    OwningGrid.Focus();
-                    //if (!e.Handled && OwningGrid.IsTabStop)
+                }
-                    {
+                if (OwningRow != null)
-                        OwningGrid.Focus();
+                {
-                    }
+                    var handled = OwningGrid.UpdateStateOnMouseLeftButtonDown(e, ColumnIndex, OwningRow.Slot, !e.Handled);
-                    if (OwningRow != null)
+
+                    // Do not handle PointerPressed with touch,
+                    // so we can start scroll gesture on the same event.
+                    if (e.Pointer.Type != PointerType.Touch)
                     {
-                        e.Handled = OwningGrid.UpdateStateOnMouseLeftButtonDown(e, ColumnIndex, OwningRow.Slot, !e.Handled);
+                        e.Handled = handled;
-                        OwningGrid.UpdatedStateOnMouseLeftButtonDown = true;
                     }
+
+                    OwningGrid.UpdatedStateOnMouseLeftButtonDown = true;
+                }
+            }
+            else if (e.GetCurrentPoint(this).Properties.IsRightButtonPressed)
+            {
+                if (!e.Handled)
+                //if (!e.Handled && OwningGrid.IsTabStop)
+                {
+                    OwningGrid.Focus();
+                }
+                if (OwningRow != null)
+                {
+                    e.Handled = OwningGrid.UpdateStateOnMouseRightButtonDown(e, ColumnIndex, OwningRow.Slot, !e.Handled);
                 }
             }
         }
@@ -197,7 +218,7 @@ namespace Avalonia.Controls
         }
 
         // Makes sure the right gridline has the proper stroke and visibility. If lastVisibleColumn is specified, the 
-        // right gridline will be collapsed if this cell belongs to the lastVisibileColumn and there is no filler column
+        // right gridline will be collapsed if this cell belongs to the lastVisibleColumn and there is no filler column
         internal void EnsureGridLine(DataGridColumn lastVisibleColumn)
         {
             if (OwningGrid != null && _rightGridLine != null)

src/Avalonia.Controls.DataGrid/DataGridCellCoordinates.cs

@@ -40,7 +40,7 @@ namespace Avalonia.Controls
             return false;
         }
 
-        // There is build warning if this is missiing
+        // There is build warning if this is missing
         public override int GetHashCode()
         {
             return base.GetHashCode();

src/Avalonia.Controls.DataGrid/DataGridClipboard.cs

@@ -189,7 +189,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// DataGrid row item used for proparing the ClipboardRowContent.
+        /// DataGrid row item used for preparing the ClipboardRowContent.
         /// </summary>
         public object Item
         {

src/Avalonia.Controls.DataGrid/DataGridColumn.cs

@@ -27,7 +27,6 @@ namespace Avalonia.Controls
         private double? _minWidth;
         private bool _settingWidthInternally;
         private int _displayIndexWithFiller;
-        private bool _isVisible;
         private object _header;
         private DataGridColumnHeader _headerCell;
         private IControl _editingElement;
@@ -40,7 +39,6 @@ namespace Avalonia.Controls
         /// </summary>
         protected internal DataGridColumn()
         {
-            _isVisible = true;
             _displayIndexWithFiller = -1;
             IsInitialDesiredWidthDetermined = false;
             InheritsWidth = true;
@@ -174,32 +172,42 @@ namespace Avalonia.Controls
             get => _editBinding;
         }
 
+
+        /// <summary>
+        /// Defines the <see cref="IsVisible"/> property.
+        /// </summary>
+        public static StyledProperty<bool> IsVisibleProperty =
+             Control.IsVisibleProperty.AddOwner<DataGridColumn>();
+
         /// <summary>
         /// Determines whether or not this column is visible.
         /// </summary>
         public bool IsVisible
         {
-            get
+            get => GetValue(IsVisibleProperty);
-            {
+            set => SetValue(IsVisibleProperty, value);
-                return _isVisible;
+        }
-            }
-            set
-            {
-                if (value != IsVisible)
-                {
-                    OwningGrid?.OnColumnVisibleStateChanging(this);
-                    _isVisible = value;
 
-                    if (_headerCell != null)
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
-                    {
+        {
-                        _headerCell.IsVisible = value;
+            base.OnPropertyChanged(change);
-                    }
 
-                    OwningGrid?.OnColumnVisibleStateChanged(this);
+            if (change.Property == IsVisibleProperty)
+            {
+                OwningGrid?.OnColumnVisibleStateChanging(this);
+                var isVisible = (change as AvaloniaPropertyChangedEventArgs<bool>).NewValue.Value;
+
+                if (_headerCell != null)
+                {
+                    _headerCell.IsVisible = isVisible;
                 }
+
+                OwningGrid?.OnColumnVisibleStateChanged(this);
+                NotifyPropertyChanged(change.Property.Name);
             }
         }
 
+
         /// <summary>
         /// Actual visible width after Width, MinWidth, and MaxWidth setting at the Column level and DataGrid level
         /// have been taken into account
@@ -787,7 +795,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// If the DataGrid is using using layout rounding, the pixel snapping will force all widths to
+        /// If the DataGrid is using layout rounding, the pixel snapping will force all widths to
         /// whole numbers. Since the column widths aren't visual elements, they don't go through the normal
         /// rounding process, so we need to do it ourselves.  If we don't, then we'll end up with some
         /// pixel gaps and/or overlaps between columns.

src/Avalonia.Controls.DataGrid/DataGridDataConnection.cs

@@ -233,7 +233,7 @@ namespace Avalonia.Controls
                 else
                 {
                     editableCollectionView.EditItem(dataItem);
-                    return editableCollectionView.IsEditingItem;
+                    return editableCollectionView.IsEditingItem || editableCollectionView.IsAddingNew;
                 }
             }
 
@@ -314,7 +314,14 @@ namespace Avalonia.Controls
                 CommittingEdit = true;
                 try
                 {
-                    editableCollectionView.CommitEdit();
+                    if (editableCollectionView.IsAddingNew)
+                    {
+                        editableCollectionView.CommitNew();
+                    }
+                    else
+                    {
+                        editableCollectionView.CommitEdit();
+                    }                    
                 }
                 finally
                 {

src/Avalonia.Controls.DataGrid/DataGridDisplayData.cs

@@ -79,7 +79,7 @@ namespace Avalonia.Controls
             set;
         }
 
-        internal void AddRecylableRow(DataGridRow row)
+        internal void AddRecyclableRow(DataGridRow row)
         {
             Debug.Assert(!_recyclableRows.Contains(row));
             row.DetachFromDataGrid(true);
@@ -120,7 +120,7 @@ namespace Avalonia.Controls
                     {
                         if (row.IsRecyclable)
                         {
-                            AddRecylableRow(row);
+                            AddRecyclableRow(row);
                         }
                         else
                         {
@@ -193,7 +193,7 @@ namespace Avalonia.Controls
 
         internal void FullyRecycleElements()
         {
-            // Fully recycle Recycleable rows and transfer them to Recycled rows
+            // Fully recycle Recyclable rows and transfer them to Recycled rows
             while (_recyclableRows.Count > 0)
             {
                 DataGridRow row = _recyclableRows.Pop();
@@ -202,7 +202,7 @@ namespace Avalonia.Controls
                 Debug.Assert(!_fullyRecycledRows.Contains(row));
                 _fullyRecycledRows.Push(row);
             }
-            // Fully recycle Recycleable GroupHeaders and transfer them to Recycled GroupHeaders
+            // Fully recycle Recyclable GroupHeaders and transfer them to Recycled GroupHeaders
             while (_recyclableGroupHeaders.Count > 0)
             {
                 DataGridRowGroupHeader groupHeader = _recyclableGroupHeaders.Pop();

src/Avalonia.Controls.DataGrid/DataGridRow.cs

@@ -378,13 +378,13 @@ namespace Avalonia.Controls
                     }
                 }
             }
-        } 
+        }
 
         internal Panel RootElement
         {
             get;
             private set;
-        } 
+        }
 
         internal int Slot
         {
@@ -392,7 +392,7 @@ namespace Avalonia.Controls
             set;
         }
 
-        // Height that the row will eventually end up at after a possible detalis animation has completed
+        // Height that the row will eventually end up at after a possible details animation has completed
         internal double TargetHeight
         {
             get
@@ -517,7 +517,7 @@ namespace Avalonia.Controls
                 return base.MeasureOverride(availableSize);
             }
 
-            //Allow the DataGrid specific componets to adjust themselves based on new values
+            //Allow the DataGrid specific components to adjust themselves based on new values
             if (_headerElement != null)
             {
                 _headerElement.InvalidateMeasure();
@@ -638,7 +638,7 @@ namespace Avalonia.Controls
                 PseudoClasses.Set(":editing", IsEditing);
                 PseudoClasses.Set(":invalid", !IsValid);
                 ApplyHeaderStatus();
-            } 
+            }
         }
 
         //TODO Animation
@@ -722,7 +722,7 @@ namespace Avalonia.Controls
                 if (_bottomGridLine != null)
                 {
                     // It looks like setting Visibility sometimes has side effects so make sure the value is actually
-                    // diffferent before setting it
+                    // different before setting it
                     bool newVisibility = OwningGrid.GridLinesVisibility == DataGridGridLinesVisibility.Horizontal || OwningGrid.GridLinesVisibility == DataGridGridLinesVisibility.All;
 
                     if (newVisibility != _bottomGridLine.IsVisible)
@@ -896,7 +896,7 @@ namespace Avalonia.Controls
                     _detailsElement.ContentHeight = _detailsDesiredHeight;
                 }
             }
-        } 
+        }
 
         // Makes sure the _detailsDesiredHeight is initialized.  We need to measure it to know what
         // height we want to animate to.  Subsequently, we just update that height in response to SizeChanged
@@ -919,7 +919,7 @@ namespace Avalonia.Controls
 
         //TODO Cleanup
         double? _previousDetailsHeight = null;
-        
+
         //TODO Animation 
         private void DetailsContent_HeightChanged(double newValue)
         {
@@ -1022,7 +1022,7 @@ namespace Avalonia.Controls
                 }
             }
         }
-        
+
         internal void ApplyDetailsTemplate(bool initializeDetailsPreferredHeight)
         {
             if (_detailsElement != null && AreDetailsVisible)
@@ -1066,7 +1066,7 @@ namespace Avalonia.Controls
                                                .Subscribe(DetailsContent_MarginChanged);
 
                         }
-                        
+
                         _detailsElement.Children.Add(_detailsContent);
                     }
                 }
@@ -1090,6 +1090,28 @@ namespace Avalonia.Controls
                 }
             }
         }
+        
+
+        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
+        {
+            if (change.Property == DataContextProperty)
+            {
+                var owner = OwningGrid;
+                if (owner != null && this.IsRecycled)
+                {
+                    var columns = owner.ColumnsItemsInternal;
+                    var nc = columns.Count;
+                    for (int ci = 0; ci < nc; ci++)
+                    {
+                        if (columns[ci] is DataGridTemplateColumn column)
+                        {
+                            column.RefreshCellContent((Control)this.Cells[column.Index].Content, nameof(DataGridTemplateColumn.CellTemplate));
+                        }
+                    }
+                }
+            }
+            base.OnPropertyChanged(change);
+        }
 
     }
 

src/Avalonia.Controls.DataGrid/DataGridRowGroupHeader.cs

@@ -283,7 +283,11 @@ namespace Avalonia.Controls
         //TODO TabStop
         private void DataGridRowGroupHeader_PointerPressed(PointerPressedEventArgs e)
         {
-            if (OwningGrid != null && e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+            if (OwningGrid == null)
+            {
+                return;
+            }
+            if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
             {
                 if (OwningGrid.IsDoubleClickRecordsClickOnCall(this) && !e.Handled)
                 {
@@ -300,6 +304,15 @@ namespace Avalonia.Controls
                     e.Handled = OwningGrid.UpdateStateOnMouseLeftButtonDown(e, OwningGrid.CurrentColumnIndex, RowGroupInfo.Slot, allowEdit: false);
                 }
             }
+            else if (e.GetCurrentPoint(this).Properties.IsRightButtonPressed)
+            {
+                if (!e.Handled)
+                {
+                    OwningGrid.Focus();
+                }
+                e.Handled = OwningGrid.UpdateStateOnMouseRightButtonDown(e, OwningGrid.CurrentColumnIndex, RowGroupInfo.Slot, allowEdit: false);
+            }
+
         }
 
         private void EnsureChildClip(Visual child, double frozenLeftEdge)

src/Avalonia.Controls.DataGrid/DataGridRowHeader.cs

@@ -179,12 +179,12 @@ namespace Avalonia.Controls.Primitives
         //TODO TabStop
         private void DataGridRowHeader_PointerPressed(object sender, PointerPressedEventArgs e)
         {
-            if (!e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
+            if (OwningGrid == null)
             {
                 return;
             }
 
-            if (OwningGrid != null)
+            if (e.GetCurrentPoint(this).Properties.IsLeftButtonPressed)
             {
                 if (!e.Handled)
                 //if (!e.Handled && OwningGrid.IsTabStop)
@@ -199,6 +199,19 @@ namespace Avalonia.Controls.Primitives
                     OwningGrid.UpdatedStateOnMouseLeftButtonDown = true;
                 }
             }
+            else if (e.GetCurrentPoint(this).Properties.IsRightButtonPressed)
+            {
+                if (!e.Handled)
+                {
+                    OwningGrid.Focus();
+                }
+                if (OwningRow != null)
+                {
+                    Debug.Assert(sender is DataGridRowHeader);
+                    Debug.Assert(sender == this);
+                    e.Handled = OwningGrid.UpdateStateOnMouseRightButtonDown(e, -1, Slot, false);
+                }
+            }
         } 
 
     }

src/Avalonia.Controls.DataGrid/DataGridRows.cs

@@ -425,7 +425,7 @@ namespace Avalonia.Controls
                 UpdateDisplayedRows(DisplayData.FirstScrollingSlot, CellsHeight);
             }
 
-            if (DisplayData.FirstScrollingSlot < slot && DisplayData.LastScrollingSlot > slot)
+            if (DisplayData.FirstScrollingSlot < slot && (DisplayData.LastScrollingSlot > slot || DisplayData.LastScrollingSlot == -1))
             {
                 // The row is already displayed in its entirety
                 return true;
@@ -1193,7 +1193,7 @@ namespace Avalonia.Controls
                 else
                 {
                     groupHeader = element as DataGridRowGroupHeader;
-                    Debug.Assert(groupHeader != null);  // Nothig other and Rows and RowGroups now
+                    Debug.Assert(groupHeader != null);  // Nothing other and Rows and RowGroups now
                     if (groupHeader != null)
                     {
                         groupHeader.TotalIndent = (groupHeader.Level == 0) ? 0 : RowGroupSublevelIndents[groupHeader.Level - 1];
@@ -1636,7 +1636,7 @@ namespace Avalonia.Controls
             if (slot >= DisplayData.FirstScrollingSlot &&
                 slot <= DisplayData.LastScrollingSlot)
             {
-                // Additional row takes the spot of a displayed row - it is necessarilly displayed
+                // Additional row takes the spot of a displayed row - it is necessarily displayed
                 return true;
             }
             else if (DisplayData.FirstScrollingSlot == -1 &&
@@ -1825,7 +1825,7 @@ namespace Avalonia.Controls
                 if (MathUtilities.LessThan(firstRowHeight, NegVerticalOffset))
                 {
                     // We've scrolled off more of the first row than what's possible.  This can happen
-                    // if the first row got shorter (Ex: Collpasing RowDetails) or if the user has a recycling
+                    // if the first row got shorter (Ex: Collapsing RowDetails) or if the user has a recycling
                     // cleanup issue.  In this case, simply try to display the next row as the first row instead
                     if (newFirstScrollingSlot < SlotCount - 1)
                     {
@@ -2014,7 +2014,7 @@ namespace Avalonia.Controls
 
             if (recycleRow)
             {
-                DisplayData.AddRecylableRow(dataGridRow);
+                DisplayData.AddRecyclableRow(dataGridRow);
             }
             else
             {
@@ -2265,7 +2265,7 @@ namespace Avalonia.Controls
                     if (parentGroupInfo.LastSubItemSlot - parentGroupInfo.Slot == 1)
                     {
                         // We just added the first item to a RowGroup so the header should transition from Empty to either Expanded or Collapsed
-                        EnsureAnscestorsExpanderButtonChecked(parentGroupInfo);
+                        EnsureAncestorsExpanderButtonChecked(parentGroupInfo);
                     }
                 }
             }
@@ -2407,7 +2407,7 @@ namespace Avalonia.Controls
             return treeCount;
         }
 
-        private void EnsureAnscestorsExpanderButtonChecked(DataGridRowGroupInfo parentGroupInfo)
+        private void EnsureAncestorsExpanderButtonChecked(DataGridRowGroupInfo parentGroupInfo)
         {
             if (IsSlotVisible(parentGroupInfo.Slot))
             {
@@ -2789,11 +2789,11 @@ namespace Avalonia.Controls
             return null;
         }
 
-        internal void OnRowGroupHeaderToggled(DataGridRowGroupHeader groupHeader, bool newIsVisibile, bool setCurrent)
+        internal void OnRowGroupHeaderToggled(DataGridRowGroupHeader groupHeader, bool newIsVisible, bool setCurrent)
         {
             Debug.Assert(groupHeader.RowGroupInfo.CollectionViewGroup.ItemCount > 0);
 
-            if (WaitForLostFocus(delegate { OnRowGroupHeaderToggled(groupHeader, newIsVisibile, setCurrent); }) || !CommitEdit())
+            if (WaitForLostFocus(delegate { OnRowGroupHeaderToggled(groupHeader, newIsVisible, setCurrent); }) || !CommitEdit())
             {
                 return;
             }
@@ -2804,7 +2804,7 @@ namespace Avalonia.Controls
                 UpdateSelectionAndCurrency(CurrentColumnIndex, groupHeader.RowGroupInfo.Slot, DataGridSelectionAction.SelectCurrent, scrollIntoView: false);
             }
 
-            UpdateRowGroupVisibility(groupHeader.RowGroupInfo, newIsVisibile, isDisplayed: true);
+            UpdateRowGroupVisibility(groupHeader.RowGroupInfo, newIsVisible, isDisplayed: true);
 
             ComputeScrollBarsLayout();
             // We need force arrange since our Scrollings Rows could update without automatically triggering layout

src/Avalonia.Controls.DataGrid/Primitives/DataGridColumnHeadersPresenter.cs

@@ -140,7 +140,7 @@ namespace Avalonia.Controls.Primitives
                 if (dataGridColumn.IsFrozen)
                 {
                     columnHeader.Arrange(new Rect(frozenLeftEdge, 0, dataGridColumn.LayoutRoundedWidth, finalSize.Height));
-                    columnHeader.Clip = null; // The layout system could have clipped this becaues it's not aware of our render transform
+                    columnHeader.Clip = null; // The layout system could have clipped this because it's not aware of our render transform
                     if (DragColumn == dataGridColumn && DragIndicator != null)
                     {
                         dragIndicatorLeftEdge = frozenLeftEdge + DragIndicatorOffset;

src/Avalonia.Controls.DataGrid/Primitives/DataGridRowsPresenter.cs

@@ -5,6 +5,9 @@
 
 using System;
 using System.Diagnostics;
+
+using Avalonia.Input;
+using Avalonia.Input.GestureRecognizers;
 using Avalonia.Layout;
 using Avalonia.Media;
 
@@ -16,6 +19,11 @@ namespace Avalonia.Controls.Primitives
     /// </summary>
     public sealed class DataGridRowsPresenter : Panel
     {
+        public DataGridRowsPresenter()
+        {
+            AddHandler(Gestures.ScrollGestureEvent, OnScrollGesture);
+        }
+
         internal DataGrid OwningGrid
         {
             get;
@@ -176,6 +184,11 @@ namespace Avalonia.Controls.Primitives
             return new Size(totalCellsWidth + headerWidth, totalHeight);
         }
 
+        private void OnScrollGesture(object sender, ScrollGestureEventArgs e)
+        {
+            e.Handled = e.Handled || OwningGrid.UpdateScroll(-e.Delta);
+        }
+
 #if DEBUG
         internal void PrintChildren()
         {

src/Avalonia.Controls.DataGrid/Themes/Default.xaml

@@ -247,7 +247,11 @@
             <DataGridColumnHeader Name="PART_TopRightCornerHeader" Grid.Column="2"/>
             <Rectangle Name="PART_ColumnHeadersAndRowsSeparator" Grid.ColumnSpan="3" VerticalAlignment="Bottom" StrokeThickness="1" Height="1" Fill="{DynamicResource ThemeControlMidHighBrush}"/>
 
-            <DataGridRowsPresenter Name="PART_RowsPresenter" Grid.ColumnSpan="2" Grid.Row="1" />
+            <DataGridRowsPresenter Name="PART_RowsPresenter" Grid.ColumnSpan="2" Grid.Row="1">
+              <DataGridRowsPresenter.GestureRecognizers>
+                <ScrollGestureRecognizer CanHorizontallyScroll="True" CanVerticallyScroll="True" />
+              </DataGridRowsPresenter.GestureRecognizers>
+            </DataGridRowsPresenter>
             <Rectangle Name="PART_BottomRightCorner" Fill="{DynamicResource ThemeControlMidHighBrush}" Grid.Column="2" Grid.Row="2" />
             <Rectangle Name="BottomLeftCorner" Fill="{DynamicResource ThemeControlMidHighBrush}" Grid.Row="2" Grid.ColumnSpan="2" />
             <ScrollBar Name="PART_VerticalScrollbar" Orientation="Vertical" Grid.Column="2" Grid.Row="1" Width="{DynamicResource ScrollBarThickness}"/>

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

@@ -6,8 +6,8 @@
     <x:Double x:Key="ListAccentLowOpacity">0.6</x:Double>
     <x:Double x:Key="ListAccentMediumOpacity">0.8</x:Double>
 
-    <StreamGeometry x:Key="DataGridSortIconAscendingPath">M1875 1011l-787 787v-1798h-128v1798l-787 -787l-90 90l941 941l941 -941z</StreamGeometry>
+    <StreamGeometry x:Key="DataGridSortIconDescendingPath">M1875 1011l-787 787v-1798h-128v1798l-787 -787l-90 90l941 941l941 -941z</StreamGeometry>
-    <StreamGeometry x:Key="DataGridSortIconDescendingPath">M1965 947l-941 -941l-941 941l90 90l787 -787v1798h128v-1798l787 787z</StreamGeometry>
+    <StreamGeometry x:Key="DataGridSortIconAscendingPath">M1965 947l-941 -941l-941 941l90 90l787 -787v1798h128v-1798l787 787z</StreamGeometry>
     <StreamGeometry x:Key="DataGridRowGroupHeaderIconClosedPath">M515 93l930 931l-930 931l90 90l1022 -1021l-1022 -1021z</StreamGeometry>
     <StreamGeometry x:Key="DataGridRowGroupHeaderIconOpenedPath">M1939 1581l90 -90l-1005 -1005l-1005 1005l90 90l915 -915z</StreamGeometry>
 
@@ -601,7 +601,11 @@
             <DataGridRowsPresenter Name="PART_RowsPresenter"
                                    Grid.Row="1"
                                    Grid.RowSpan="2"
-                                   Grid.ColumnSpan="3" />
+                                   Grid.ColumnSpan="3">
+              <DataGridRowsPresenter.GestureRecognizers>
+                <ScrollGestureRecognizer CanHorizontallyScroll="True" CanVerticallyScroll="True" />
+              </DataGridRowsPresenter.GestureRecognizers>
+            </DataGridRowsPresenter>
             <Rectangle Name="PART_BottomRightCorner"
                        Fill="{DynamicResource DataGridScrollBarsSeparatorBackground}"
                        Grid.Column="2"

src/Avalonia.Controls.DataGrid/Utils/CellEditBinding.cs

@@ -1,10 +1,8 @@
 using Avalonia.Data;
 using Avalonia.Reactive;
 using System;
-using System.ComponentModel.DataAnnotations;
 using System.Collections.Generic;
 using System.Reactive.Subjects;
-using System.Text;
 
 namespace Avalonia.Controls.Utils
 {
@@ -67,11 +65,14 @@ namespace Avalonia.Controls.Utils
 
             private void SetSourceValue(object value)
             {
-                _settingSourceValue = true;
+                if (!_settingSourceValue)
+                {
+                    _settingSourceValue = true;
 
-                _sourceSubject.OnNext(value);
+                    _sourceSubject.OnNext(value);
 
-                _settingSourceValue = false;
+                    _settingSourceValue = false;
+                }
             }
             private void SetControlValue(object value)
             {
@@ -157,4 +158,4 @@ namespace Avalonia.Controls.Utils
             }
         }
     }
-}
+}

src/Avalonia.Controls.DataGrid/Utils/ReflectionHelper.cs

@@ -340,10 +340,30 @@ namespace Avalonia.Controls.Utils
         internal static PropertyInfo GetPropertyOrIndexer(this Type type, string propertyPath, out object[] index)
         {
             index = null;
+            // Return the default value of GetProperty if the first character is not an indexer token.
             if (string.IsNullOrEmpty(propertyPath) || propertyPath[0] != LeftIndexerToken)
             {
-                // Return the default value of GetProperty if the first character is not an indexer token.
+                var property = type.GetProperty(propertyPath);
-                return type.GetProperty(propertyPath);
+                if (property != null)
+                {
+                    return property;
+                }
+
+                // GetProperty does not return inherited interface properties,
+                // so we need to enumerate them manually.
+                if (type.IsInterface)
+                {
+                    foreach (var typeInterface in type.GetInterfaces())
+                    {
+                        property = type.GetProperty(propertyPath);
+                        if (property != null)
+                        {
+                            return property;
+                        }
+                    }
+                }
+
+                return null;
             }
 
             if (propertyPath.Length < 2 || propertyPath[propertyPath.Length - 1] != RightIndexerToken)

src/Avalonia.Controls/ApiCompatBaseline.txt

@@ -4,11 +4,55 @@ InterfacesShouldHaveSameMembers : Interface member 'public System.Boolean Avalon
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.IMenuItem.StaysOpenOnClick.set(System.Boolean)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.INativeMenuExporterEventsImplBridge.RaiseClosed()' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.INativeMenuExporterEventsImplBridge.RaiseOpening()' is present in the implementation but not in the contract.
+MembersMustExist : Member 'public Avalonia.DirectProperty<Avalonia.Controls.NumericUpDown, System.Double> Avalonia.DirectProperty<Avalonia.Controls.NumericUpDown, System.Double> Avalonia.Controls.NumericUpDown.ValueProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.Double> Avalonia.StyledProperty<System.Double> Avalonia.Controls.NumericUpDown.IncrementProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.Double> Avalonia.StyledProperty<System.Double> Avalonia.Controls.NumericUpDown.MaximumProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.Double> Avalonia.StyledProperty<System.Double> Avalonia.Controls.NumericUpDown.MinimumProperty' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDown.Increment.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.NumericUpDown.Increment.set(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDown.Maximum.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.NumericUpDown.Maximum.set(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDown.Minimum.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.NumericUpDown.Minimum.set(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected System.Double Avalonia.Controls.NumericUpDown.OnCoerceIncrement(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected System.Double Avalonia.Controls.NumericUpDown.OnCoerceMaximum(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected System.Double Avalonia.Controls.NumericUpDown.OnCoerceMinimum(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected System.Double Avalonia.Controls.NumericUpDown.OnCoerceValue(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected void Avalonia.Controls.NumericUpDown.OnIncrementChanged(System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected void Avalonia.Controls.NumericUpDown.OnMaximumChanged(System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected void Avalonia.Controls.NumericUpDown.OnMinimumChanged(System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected void Avalonia.Controls.NumericUpDown.OnValueChanged(System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected void Avalonia.Controls.NumericUpDown.RaiseValueChangedEvent(System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDown.Value.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.NumericUpDown.Value.set(System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.NumericUpDownValueChangedEventArgs..ctor(Avalonia.Interactivity.RoutedEvent, System.Double, System.Double)' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDownValueChangedEventArgs.NewValue.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public System.Double Avalonia.Controls.NumericUpDownValueChangedEventArgs.OldValue.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public Avalonia.StyledProperty<System.Boolean> Avalonia.StyledProperty<System.Boolean> Avalonia.Controls.ScrollViewer.AllowAutoHideProperty' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public Avalonia.AvaloniaProperty<Avalonia.Media.Stretch> Avalonia.AvaloniaProperty<Avalonia.Media.Stretch> Avalonia.Controls.Viewbox.StretchProperty' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs> Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.ShutdownRequested' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.add_ShutdownRequested(System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs>)' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.ApplicationLifetimes.IClassicDesktopStyleApplicationLifetime.remove_ShutdownRequested(System.EventHandler<Avalonia.Controls.ApplicationLifetimes.ShutdownRequestedEventArgs>)' is present in the implementation but not in the contract.
+MembersMustExist : Member 'public System.Action<Avalonia.Size> Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.Resized.get()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.Resized.set(System.Action<Avalonia.Size>)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public Avalonia.AvaloniaProperty Avalonia.AvaloniaProperty Avalonia.Controls.Notifications.NotificationCard.CloseOnClickProperty' does not exist in the implementation but it does exist in the contract.
 EnumValuesMustMatch : Enum value 'Avalonia.Platform.ExtendClientAreaChromeHints Avalonia.Platform.ExtendClientAreaChromeHints.Default' is (System.Int32)2 in the implementation but (System.Int32)1 in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Nullable<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.FrameSize.get()' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Action<Avalonia.Size, Avalonia.Platform.PlatformResizeReason> Avalonia.Platform.ITopLevelImpl.Resized.get()' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public System.Action<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.Resized.get()' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public System.Action<Avalonia.Size> Avalonia.Platform.ITopLevelImpl.Resized.get()' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size, Avalonia.Platform.PlatformResizeReason>)' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size>)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public void Avalonia.Platform.ITopLevelImpl.Resized.set(System.Action<Avalonia.Size>)' does not exist in the implementation but it does exist in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.ICursorImpl)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' is present in the contract but not in the implementation.
 MembersMustExist : Member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
-Total Issues: 12
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowBaseImpl.Show(System.Boolean, System.Boolean)' is present in the implementation but not in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size)' is present in the contract but not in the implementation.
+MembersMustExist : Member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size)' does not exist in the implementation but it does exist in the contract.
+InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.IWindowImpl.Resize(Avalonia.Size, Avalonia.Platform.PlatformResizeReason)' is present in the implementation but not in the contract.
+Total Issues: 56

src/Avalonia.Controls/AppBuilderBase.cs

@@ -273,7 +273,7 @@ namespace Avalonia.Controls
         }
         
         /// <summary>
-        /// Sets up the platform-speciic services for the <see cref="Application"/>.
+        /// Sets up the platform-specific services for the <see cref="Application"/>.
         /// </summary>
         private void Setup()
         {

src/Avalonia.Controls/Application.cs

@@ -13,6 +13,7 @@ using Avalonia.Platform;
 using Avalonia.Rendering;
 using Avalonia.Styling;
 using Avalonia.Threading;
+#nullable enable
 
 namespace Avalonia
 {
@@ -35,27 +36,27 @@ namespace Avalonia
         /// <summary>
         /// The application-global data templates.
         /// </summary>
-        private DataTemplates _dataTemplates;
+        private DataTemplates? _dataTemplates;
 
         private readonly Lazy<IClipboard> _clipboard =
             new Lazy<IClipboard>(() => (IClipboard)AvaloniaLocator.Current.GetService(typeof(IClipboard)));
         private readonly Styler _styler = new Styler();
-        private Styles _styles;
+        private Styles? _styles;
-        private IResourceDictionary _resources;
+        private IResourceDictionary? _resources;
         private bool _notifyingResourcesChanged;
-        private Action<IReadOnlyList<IStyle>> _stylesAdded;
+        private Action<IReadOnlyList<IStyle>>? _stylesAdded;
-        private Action<IReadOnlyList<IStyle>> _stylesRemoved;
+        private Action<IReadOnlyList<IStyle>>? _stylesRemoved;
 
         /// <summary>
         /// Defines the <see cref="DataContext"/> property.
         /// </summary>
-        public static readonly StyledProperty<object> DataContextProperty =
+        public static readonly StyledProperty<object?> DataContextProperty =
             StyledElement.DataContextProperty.AddOwner<Application>();
 
         /// <inheritdoc/>
-        public event EventHandler<ResourcesChangedEventArgs> ResourcesChanged;
+        public event EventHandler<ResourcesChangedEventArgs>? ResourcesChanged;
 
-        public event EventHandler<UrlOpenedEventArgs> UrlsOpened; 
+        public event EventHandler<UrlOpenedEventArgs>? UrlsOpened; 
 
         /// <summary>
         /// Creates an instance of the <see cref="Application"/> class.
@@ -72,7 +73,7 @@ namespace Avalonia
         /// The data context property specifies the default object that will
         /// be used for data binding.
         /// </remarks>
-        public object DataContext
+        public object? DataContext
         {
             get { return GetValue(DataContextProperty); }
             set { SetValue(DataContextProperty, value); }
@@ -162,7 +163,7 @@ namespace Avalonia
         /// <summary>
         /// Gets the styling parent of the application, which is null.
         /// </summary>
-        IStyleHost IStyleHost.StylingParent => null;
+        IStyleHost? IStyleHost.StylingParent => null;
 
         /// <inheritdoc/>
         bool IStyleHost.IsStylesInitialized => _styles != null;
@@ -194,7 +195,7 @@ namespace Avalonia
         public virtual void Initialize() { }
 
         /// <inheritdoc/>
-        bool IResourceNode.TryGetResource(object key, out object value)
+        bool IResourceNode.TryGetResource(object key, out object? value)
         {
             value = null;
             return (_resources?.TryGetResource(key, out value) ?? false) ||
@@ -279,17 +280,17 @@ namespace Avalonia
             NotifyResourcesChanged(e);
         }
 
-        private string _name;
+        private string? _name;
         /// <summary>
         /// Defines Name property
         /// </summary>
-        public static readonly DirectProperty<Application, string> NameProperty =
+        public static readonly DirectProperty<Application, string?> NameProperty =
-            AvaloniaProperty.RegisterDirect<Application, string>("Name", o => o.Name, (o, v) => o.Name = v);
+            AvaloniaProperty.RegisterDirect<Application, string?>("Name", o => o.Name, (o, v) => o.Name = v);
 
         /// <summary>
         /// Application name to be used for various platform-specific purposes
         /// </summary>
-        public string Name
+        public string? Name
         {
             get => _name;
             set => SetAndRaise(NameProperty, ref _name, value);

src/Avalonia.Controls/ApplicationLifetimes/ClassicDesktopStyleApplicationLifetime.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Threading;
 using Avalonia.Controls;
@@ -42,9 +43,13 @@ namespace Avalonia.Controls.ApplicationLifetimes
                     "Can not have multiple active ClassicDesktopStyleApplicationLifetime instances and the previously created one was not disposed");
             _activeLifetime = this;
         }
-        
+
         /// <inheritdoc/>
         public event EventHandler<ControlledApplicationLifetimeStartupEventArgs> Startup;
+
+        /// <inheritdoc/>
+        public event EventHandler<ShutdownRequestedEventArgs> ShutdownRequested;
+
         /// <inheritdoc/>
         public event EventHandler<ControlledApplicationLifetimeExitEventArgs> Exit;
 
@@ -111,6 +116,11 @@ namespace Avalonia.Controls.ApplicationLifetimes
                 ((IApplicationPlatformEvents)Application.Current).RaiseUrlsOpened(args);
             }
 
+            var lifetimeEvents = AvaloniaLocator.Current.GetService<IPlatformLifetimeEventsImpl>(); 
+
+            if (lifetimeEvents != null)
+                lifetimeEvents.ShutdownRequested += OnShutdownRequested;
+
             _cts = new CancellationTokenSource();
             MainWindow?.Show();
             Dispatcher.UIThread.MainLoop(_cts.Token);
@@ -123,6 +133,23 @@ namespace Avalonia.Controls.ApplicationLifetimes
             if (_activeLifetime == this)
                 _activeLifetime = null;
         }
+        
+        private void OnShutdownRequested(object sender, ShutdownRequestedEventArgs e)
+        {
+            ShutdownRequested?.Invoke(this, e);
+
+            if (e.Cancel)
+                return;
+
+            // When an OS shutdown request is received, try to close all non-owned windows. Windows can cancel
+            // shutdown by setting e.Cancel = true in the Closing event. Owned windows will be shutdown by their
+            // owners.
+            foreach (var w in Windows)
+                if (w.Owner is null)
+                    w.Close();
+            if (Windows.Count > 0)
+                e.Cancel = true;
+        }
     }
     
     public class ClassicDesktopStyleApplicationLifetimeOptions

src/Avalonia.Controls/ApplicationLifetimes/IClassicDesktopStyleApplicationLifetime.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 
 namespace Avalonia.Controls.ApplicationLifetimes
 {
@@ -34,5 +35,23 @@ namespace Avalonia.Controls.ApplicationLifetimes
         Window MainWindow { get; set; }
         
         IReadOnlyList<Window> Windows { get; }
+
+        /// <summary>
+        /// Raised by the platform when an application shutdown is requested.
+        /// </summary>
+        /// <remarks>
+        /// Application Shutdown can be requested for various reasons like OS shutdown.
+        /// 
+        /// On Windows this will be called when an OS Session (logout or shutdown) terminates. Cancelling the eventargs will 
+        /// block OS shutdown.
+        /// 
+        /// On OSX this has the same behavior as on Windows and in addition:
+        /// This event is raised via the Quit menu or right-clicking on the application icon and selecting Quit. 
+        /// 
+        /// This event provides a first-chance to cancel application shutdown; if shutdown is not canceled at this point the application
+        /// will try to close each non-owned open window, invoking the <see cref="Window.Closing"/> event on each and allowing
+        /// each window to cancel the shutdown of the application. Windows cannot however prevent OS shutdown.
+        /// </remarks>
+        event EventHandler<ShutdownRequestedEventArgs> ShutdownRequested;
     }
 }

src/Avalonia.Controls/ApplicationLifetimes/ShutdownRequestedEventArgs.cs

@@ -0,0 +1,9 @@
+using System.ComponentModel;
+
+namespace Avalonia.Controls.ApplicationLifetimes
+{
+    public class ShutdownRequestedEventArgs : CancelEventArgs
+    {
+
+    }
+}

src/Avalonia.Controls/AutoCompleteBox.cs

@@ -2005,7 +2005,7 @@ namespace Avalonia.Controls
             // The TextBox.TextChanged event was not firing immediately and
             // was causing an immediate update, even with wrapping. If there is
             // a selection currently, no update should happen.
-            if (IsTextCompletionEnabled && TextBox != null && TextBoxSelectionLength > 0 && TextBoxSelectionStart != TextBox.Text.Length)
+            if (IsTextCompletionEnabled && TextBox != null && TextBoxSelectionLength > 0 && TextBoxSelectionStart != (TextBox.Text?.Length ?? 0))
             {
                 return;
             }
@@ -2094,7 +2094,21 @@ namespace Avalonia.Controls
                 bool inResults = !(stringFiltering || objectFiltering);
                 if (!inResults)
                 {
-                    inResults = stringFiltering ? TextFilter(text, FormatValue(item)) : ItemFilter(text, item);
+                    if (stringFiltering)
+                    {
+                        inResults = TextFilter(text, FormatValue(item));
+                    }
+                    else
+                    {
+                        if (ItemFilter is null)
+                        {
+                            throw new Exception("ItemFilter property can not be null when FilterMode has value AutoCompleteFilterMode.Custom");
+                        }
+                        else
+                        {
+                            inResults = ItemFilter(text, item);
+                        }
+                    }
                 }
 
                 if (view_count > view_index && inResults && _view[view_index] == item)
@@ -2303,7 +2317,7 @@ namespace Avalonia.Controls
             {
                 if (IsTextCompletionEnabled && TextBox != null && userInitiated)
                 {
-                    int currentLength = TextBox.Text.Length;
+                    int currentLength = TextBox.Text?.Length ?? 0;
                     int selectionStart = TextBoxSelectionStart;
                     if (selectionStart == text.Length && selectionStart > _textSelectionStart)
                     {

src/Avalonia.Controls/ComboBox.cs

@@ -2,7 +2,9 @@ using System;
 using System.Linq;
 using Avalonia.Automation.Peers;
 using Avalonia.Automation.Platform;
+using System.Reactive.Disposables;
 using Avalonia.Controls.Generators;
+using Avalonia.Controls.Mixins;
 using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Shapes;
@@ -79,18 +81,10 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
             ContentControl.VerticalContentAlignmentProperty.AddOwner<ComboBox>();
 
-        /// <summary>
-        /// Defines the <see cref="IsTextSearchEnabled"/> property.
-        /// </summary>
-        public static readonly StyledProperty<bool> IsTextSearchEnabledProperty =
-            AvaloniaProperty.Register<ComboBox, bool>(nameof(IsTextSearchEnabled), true);
-
-        private string _textSearchTerm = string.Empty;
-        private DispatcherTimer _textSearchTimer;
         private bool _isDropDownOpen;
         private Popup _popup;
         private object _selectionBoxItem;
-        private IDisposable _subscriptionsOnOpen;
+        private readonly CompositeDisposable _subscriptionsOnOpen = new CompositeDisposable();
 
         /// <summary>
         /// Initializes static members of the <see cref="ComboBox"/> class.
@@ -101,6 +95,7 @@ namespace Avalonia.Controls
             FocusableProperty.OverrideDefaultValue<ComboBox>(true);
             SelectedItemProperty.Changed.AddClassHandler<ComboBox>((x,e) => x.SelectedItemChanged(e));
             KeyDownEvent.AddClassHandler<ComboBox>((x, e) => x.OnKeyDown(e), Interactivity.RoutingStrategies.Tunnel);
+            IsTextSearchEnabledProperty.OverrideDefaultValue<ComboBox>(true);
         }
 
         /// <summary>
@@ -175,15 +170,6 @@ namespace Avalonia.Controls
             set { SetValue(VerticalContentAlignmentProperty, value); }
         }
 
-        /// <summary>
-        /// Gets or sets a value that specifies whether a user can jump to a value by typing.
-        /// </summary>
-        public bool IsTextSearchEnabled
-        {
-            get { return GetValue(IsTextSearchEnabledProperty); }
-            set { SetValue(IsTextSearchEnabledProperty, value); }
-        }
-
         /// <inheritdoc/>
         protected override IItemContainerGenerator CreateItemContainerGenerator()
         {
@@ -207,7 +193,7 @@ namespace Avalonia.Controls
             if (e.Handled)
                 return;
 
-            if (e.Key == Key.F4 ||
+            if ((e.Key == Key.F4 && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt) == false) ||
                 ((e.Key == Key.Down || e.Key == Key.Up) && e.KeyModifiers.HasAllFlags(KeyModifiers.Alt)))
             {
                 IsDropDownOpen = !IsDropDownOpen;
@@ -249,32 +235,6 @@ namespace Avalonia.Controls
             }
         }
 
-        /// <inheritdoc />
-        protected override void OnTextInput(TextInputEventArgs e)
-        {
-            if (!IsTextSearchEnabled || e.Handled)
-                return;
-
-            StopTextSearchTimer();
-
-            _textSearchTerm += e.Text;
-
-            bool match(ItemContainerInfo info) => 
-                info.ContainerControl is IContentControl control &&
-                control.Content?.ToString()?.StartsWith(_textSearchTerm, StringComparison.OrdinalIgnoreCase) == true;
-
-            var info = ItemContainerGenerator.Containers.FirstOrDefault(match);
-
-            if (info != null)
-            {
-                SelectedIndex = info.Index;
-            }
-
-            StartTextSearchTimer();
-
-            e.Handled = true;
-        }
-
         /// <inheritdoc/>
         protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
         {
@@ -335,6 +295,7 @@ namespace Avalonia.Controls
 
             _popup = e.NameScope.Get<Popup>("PART_Popup");
             _popup.Opened += PopupOpened;
+            _popup.Closed += PopupClosed;
         }
 
         protected override AutomationPeer OnCreateAutomationPeer(IAutomationNodeFactory factory)
@@ -352,8 +313,7 @@ namespace Avalonia.Controls
 
         private void PopupClosed(object sender, EventArgs e)
         {
-            _subscriptionsOnOpen?.Dispose();
+            _subscriptionsOnOpen.Clear();
-            _subscriptionsOnOpen = null;
 
             if (CanFocus(this))
             {
@@ -365,20 +325,34 @@ namespace Avalonia.Controls
         {
             TryFocusSelectedItem();
 
-            _subscriptionsOnOpen?.Dispose();
+            _subscriptionsOnOpen.Clear();
-            _subscriptionsOnOpen = null;
 
             var toplevel = this.GetVisualRoot() as TopLevel;
             if (toplevel != null)
             {
-                _subscriptionsOnOpen = toplevel.AddDisposableHandler(PointerWheelChangedEvent, (s, ev) =>
+                toplevel.AddDisposableHandler(PointerWheelChangedEvent, (s, ev) =>
                 {
                     //eat wheel scroll event outside dropdown popup while it's open
                     if (IsDropDownOpen && (ev.Source as IVisual).GetVisualRoot() == toplevel)
                     {
                         ev.Handled = true;
                     }
-                }, Interactivity.RoutingStrategies.Tunnel);
+                }, Interactivity.RoutingStrategies.Tunnel).DisposeWith(_subscriptionsOnOpen);
+            }
+
+            this.GetObservable(IsVisibleProperty).Subscribe(IsVisibleChanged).DisposeWith(_subscriptionsOnOpen);
+
+            foreach (var parent in this.GetVisualAncestors().OfType<IControl>())
+            {
+                parent.GetObservable(IsVisibleProperty).Subscribe(IsVisibleChanged).DisposeWith(_subscriptionsOnOpen);
+            }
+        }
+
+        private void IsVisibleChanged(bool isVisible)
+        {
+            if (!isVisible && IsDropDownOpen)
+            {
+                IsDropDownOpen = false;
             }
         }
 
@@ -477,31 +451,5 @@ namespace Avalonia.Controls
 
             SelectedIndex = prev;
         }
-
-        private void StartTextSearchTimer()
-        {
-            _textSearchTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(1) };
-            _textSearchTimer.Tick += TextSearchTimer_Tick;
-            _textSearchTimer.Start();
-        }
-
-        private void StopTextSearchTimer()
-        {
-            if (_textSearchTimer == null)
-            {
-                return;
-            }
-
-            _textSearchTimer.Stop();
-            _textSearchTimer.Tick -= TextSearchTimer_Tick;
-
-            _textSearchTimer = null;
-        }
-
-        private void TextSearchTimer_Tick(object sender, EventArgs e)
-        {
-            _textSearchTerm = string.Empty;
-            StopTextSearchTimer();
-        }
     }
 }

src/Avalonia.Controls/ContextMenu.cs

@@ -3,12 +3,15 @@ using System.Collections.Generic;
 using System.ComponentModel;
 using Avalonia.Automation.Peers;
 using Avalonia.Automation.Platform;
+using System.Linq;
+using Avalonia.Controls.Diagnostics;
 using Avalonia.Controls.Generators;
 using Avalonia.Controls.Platform;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Primitives.PopupPositioning;
 using Avalonia.Controls.Templates;
 using Avalonia.Input;
+using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using Avalonia.Layout;
 using Avalonia.Styling;
@@ -20,7 +23,7 @@ namespace Avalonia.Controls
     /// <summary>
     /// A control context menu.
     /// </summary>
-    public class ContextMenu : MenuBase, ISetterValue
+    public class ContextMenu : MenuBase, ISetterValue, IPopupHostProvider
     {
         /// <summary>
         /// Defines the <see cref="HorizontalOffset"/> property.
@@ -81,6 +84,7 @@ namespace Avalonia.Controls
         private Popup? _popup;
         private List<Control>? _attachedControls;
         private IInputElement? _previousFocus;
+        private Action<IPopupHost?>? _popupHostChangedHandler;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="ContextMenu"/> class.
@@ -222,7 +226,8 @@ namespace Avalonia.Controls
 
             if (e.OldValue is ContextMenu oldMenu)
             {
-                control.PointerReleased -= ControlPointerReleased;
+                control.ContextRequested -= ControlContextRequested;
+                control.DetachedFromVisualTree -= ControlDetachedFromVisualTree;
                 oldMenu._attachedControls?.Remove(control);
                 ((ISetLogicalParent?)oldMenu._popup)?.SetParent(null);
             }
@@ -231,7 +236,8 @@ namespace Avalonia.Controls
             {
                 newMenu._attachedControls ??= new List<Control>();
                 newMenu._attachedControls.Add(control);
-                control.PointerReleased += ControlPointerReleased;
+                control.ContextRequested += ControlContextRequested;
+                control.DetachedFromVisualTree += ControlDetachedFromVisualTree;
             }
         }
 
@@ -271,7 +277,7 @@ namespace Avalonia.Controls
             }
 
             control ??= _attachedControls![0];
-            Open(control, PlacementTarget ?? control);
+            Open(control, PlacementTarget ?? control, false);
         }
 
         /// <summary>
@@ -301,6 +307,14 @@ namespace Avalonia.Controls
             }
         }
 
+        IPopupHost? IPopupHostProvider.PopupHost => _popup?.Host;
+
+        event Action<IPopupHost?>? IPopupHostProvider.PopupHostChanged 
+        { 
+            add => _popupHostChangedHandler += value; 
+            remove => _popupHostChangedHandler -= value;
+        }
+
         protected override IItemContainerGenerator CreateItemContainerGenerator()
         {
             return new MenuItemContainerGenerator(this);
@@ -311,7 +325,7 @@ namespace Avalonia.Controls
             return new ContextMenuAutomationPeer(factory, this);
         }
 
-        private void Open(Control control, Control placementTarget)
+        private void Open(Control control, Control placementTarget, bool requestedByPointer)
         {
             if (IsOpen)
             {
@@ -336,6 +350,8 @@ namespace Avalonia.Controls
 
                 _popup.Opened += PopupOpened;
                 _popup.Closed += PopupClosed;
+                _popup.Closing += PopupClosing;
+                _popup.KeyUp += PopupKeyUp;
             }
 
             if (_popup.Parent != control)
@@ -344,6 +360,10 @@ namespace Avalonia.Controls
                 ((ISetLogicalParent)_popup).SetParent(control);
             }
 
+            _popup.PlacementMode = !requestedByPointer && PlacementMode == PlacementMode.Pointer
+                ? PlacementMode.Bottom
+                : PlacementMode;
+
             _popup.PlacementTarget = placementTarget;
             _popup.Child = this;
             IsOpen = true;
@@ -360,6 +380,13 @@ namespace Avalonia.Controls
         {
             _previousFocus = FocusManager.Instance?.Current;
             Focus();
+
+            _popupHostChangedHandler?.Invoke(_popup!.Host);
+        }
+
+        private void PopupClosing(object sender, CancelEventArgs e)
+        {
+            e.Cancel = CancelClosing();
         }
 
         private void PopupClosed(object sender, EventArgs e)
@@ -388,32 +415,47 @@ namespace Avalonia.Controls
                 RoutedEvent = MenuClosedEvent,
                 Source = this,
             });
+            
+            _popupHostChangedHandler?.Invoke(null);
         }
 
-        private static void ControlPointerReleased(object sender, PointerReleasedEventArgs e)
+        private void PopupKeyUp(object sender, KeyEventArgs e)
         {
-            var control = (Control)sender;
+            if (IsOpen)
-            var contextMenu = control.ContextMenu;
-
-            if (control.ContextMenu.IsOpen)
             {
-                if (contextMenu.CancelClosing())
+                var keymap = AvaloniaLocator.Current.GetService<PlatformHotkeyConfiguration>();
-                    return;
 
-                control.ContextMenu.Close();
+                if (keymap.OpenContextMenu.Any(k => k.Matches(e))
-                e.Handled = true;
+                    && !CancelClosing())
+                {
+                    Close();
+                    e.Handled = true;
+                }
             }
+        }
 
-            if (e.InitialPressMouseButton == MouseButton.Right)
+        private static void ControlContextRequested(object sender, ContextRequestedEventArgs e)
+        {
+            if (sender is Control control
+                && control.ContextMenu is ContextMenu contextMenu
+                && !e.Handled
+                && !contextMenu.CancelOpening())
             {
-                if (contextMenu.CancelOpening())
+                var requestedByPointer = e.TryGetPosition(null, out _);
-                    return;
+                contextMenu.Open(control, e.Source as Control ?? control, requestedByPointer);
-
-                contextMenu.Open(control, e.Source as Control ?? control);
                 e.Handled = true;
             }
         }
 
+        private static void ControlDetachedFromVisualTree(object sender, VisualTreeAttachmentEventArgs e)
+        {
+            if (sender is Control control
+                && control.ContextMenu is ContextMenu contextMenu)
+            {
+                contextMenu.Close();
+            }
+        }
+
         private bool CancelClosing()
         {
             var eventArgs = new CancelEventArgs();

src/Avalonia.Controls/ContextRequestedEventArgs.cs

@@ -0,0 +1,58 @@
+using Avalonia.Input;
+using Avalonia.Interactivity;
+
+#nullable enable
+
+namespace Avalonia.Controls
+{
+    /// <summary>
+    /// Provides event data for the ContextRequested event.
+    /// </summary>
+    public class ContextRequestedEventArgs : RoutedEventArgs
+    {
+        private readonly PointerEventArgs? _pointerEventArgs;
+
+        /// <summary>
+        /// Initializes a new instance of the ContextRequestedEventArgs class.
+        /// </summary>
+        public ContextRequestedEventArgs()
+            : base(Control.ContextRequestedEvent)
+        {
+
+        }
+
+        /// <inheritdoc cref="ContextRequestedEventArgs()" />
+        public ContextRequestedEventArgs(PointerEventArgs pointerEventArgs)
+            : this()
+        {
+            _pointerEventArgs = pointerEventArgs;
+        }
+
+        /// <summary>
+        /// Gets the x- and y-coordinates of the pointer position, optionally evaluated against a coordinate origin of a supplied <see cref="Control"/>.
+        /// </summary>
+        /// <param name="relativeTo">
+        /// Any <see cref="Control"/>-derived object that is connected to the same object tree.
+        /// To specify the object relative to the overall coordinate system, use a relativeTo  value of null.
+        /// </param>
+        /// <param name="point">
+        /// A <see cref="Point"/> that represents the current x- and y-coordinates of the mouse pointer position.
+        /// If null was passed as relativeTo, this coordinate is for the overall window.
+        /// If a relativeTo value other than null was passed, this coordinate is relative to the object referenced by relativeTo.
+        /// </param>
+        /// <returns>
+        /// true if the context request was initiated by a pointer device; otherwise, false.
+        /// </returns>
+        public bool TryGetPosition(Control? relativeTo, out Point point)
+        {
+            if (_pointerEventArgs is null)
+            {
+                point = default;
+                return false;
+            }
+
+            point = _pointerEventArgs.GetPosition(relativeTo);
+            return true;
+        }
+    }
+}

src/Avalonia.Controls/Control.cs

@@ -5,6 +5,7 @@ using Avalonia.Automation.Platform;
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Templates;
 using Avalonia.Input;
+using Avalonia.Input.Platform;
 using Avalonia.Interactivity;
 using Avalonia.Rendering;
 using Avalonia.Styling;
@@ -21,6 +22,7 @@ namespace Avalonia.Controls
     /// The control class extends <see cref="InputElement"/> and adds the following features:
     ///
     /// - A <see cref="Tag"/> property to allow user-defined data to be attached to the control.
+    /// - <see cref="ContextRequestedEvent"/> and other context menu related members.
     /// </remarks>
     public class Control : InputElement, IControl, INamed, IVisualBrushInitialize, ISetterValue
     {
@@ -54,6 +56,13 @@ namespace Avalonia.Controls
         public static readonly RoutedEvent<RequestBringIntoViewEventArgs> RequestBringIntoViewEvent =
             RoutedEvent.Register<Control, RequestBringIntoViewEventArgs>("RequestBringIntoView", RoutingStrategies.Bubble);
 
+        /// <summary>
+        /// Provides event data for the <see cref="ContextRequested"/> event.
+        /// </summary>
+        public static readonly RoutedEvent<ContextRequestedEventArgs> ContextRequestedEvent =
+            RoutedEvent.Register<Control, ContextRequestedEventArgs>(nameof(ContextRequested),
+                RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
+
         private DataTemplates? _dataTemplates;
         private IControl? _focusAdorner;
         private AutomationPeer? _automationPeer;
@@ -103,6 +112,15 @@ namespace Avalonia.Controls
             set => SetValue(TagProperty, value);
         }
 
+        /// <summary>
+        /// Occurs when the user has completed a context input gesture, such as a right-click.
+        /// </summary>
+        public event EventHandler<ContextRequestedEventArgs> ContextRequested
+        {
+            add => AddHandler(ContextRequestedEvent, value);
+            remove => RemoveHandler(ContextRequestedEvent, value);
+        }
+
         public new IControl? Parent => (IControl?)base.Parent;
 
         /// <inheritdoc/>
@@ -236,5 +254,49 @@ namespace Avalonia.Controls
                 throw new InvalidOperationException("Automation peer is already set.");
             _automationPeer = peer ?? throw new ArgumentNullException(nameof(peer));
         }
+
+        protected override void OnPointerReleased(PointerReleasedEventArgs e)
+        {
+            base.OnPointerReleased(e);
+
+            if (e.Source == this
+                && !e.Handled
+                && e.InitialPressMouseButton == MouseButton.Right)
+            {
+                var args = new ContextRequestedEventArgs(e);
+                RaiseEvent(args);
+                e.Handled = args.Handled;
+            }
+        }
+
+        protected override void OnKeyUp(KeyEventArgs e)
+        {
+            base.OnKeyUp(e);
+
+            if (e.Source == this
+                && !e.Handled)
+            {
+                var keymap = AvaloniaLocator.Current.GetService<PlatformHotkeyConfiguration>().OpenContextMenu;
+                var matches = false;
+
+                for (var index = 0; index < keymap.Count; index++)
+                {
+                    var key = keymap[index];
+                    matches |= key.Matches(e);
+
+                    if (matches)
+                    {
+                        break;
+                    }
+                }
+
+                if (matches)
+                {
+                    var args = new ContextRequestedEventArgs();
+                    RaiseEvent(args);
+                    e.Handled = args.Handled;
+                }
+            }
+        }
     }
 }

src/Avalonia.Controls/Converters/MarginMultiplierConverter.cs

@@ -26,13 +26,13 @@ namespace Avalonia.Controls.Converters
                     Right ? Indent * scalarDepth : 0,
                     Bottom ? Indent * scalarDepth : 0);
             }
-            else if (value is Thickness thinknessDepth)
+            else if (value is Thickness thicknessDepth)
             {
                 return new Thickness(
-                    Left ? Indent * thinknessDepth.Left : 0,
+                    Left ? Indent * thicknessDepth.Left : 0,
-                    Top ? Indent * thinknessDepth.Top : 0,
+                    Top ? Indent * thicknessDepth.Top : 0,
-                    Right ? Indent * thinknessDepth.Right : 0,
+                    Right ? Indent * thicknessDepth.Right : 0,
-                    Bottom ? Indent * thinknessDepth.Bottom : 0);
+                    Bottom ? Indent * thicknessDepth.Bottom : 0);
             }
             return new Thickness(0);
             

src/Avalonia.Controls/Converters/MenuScrollingVisibilityConverter.cs

@@ -16,7 +16,7 @@ namespace Avalonia.Controls.Converters
             if (parameter == null ||
                 values == null ||
                 values.Count != 4 ||
-                !(values[0] is ScrollBarVisibility visiblity) ||
+                !(values[0] is ScrollBarVisibility visibility) ||
                 !(values[1] is double offset) ||
                 !(values[2] is double extent) ||
                 !(values[3] is double viewport))
@@ -24,7 +24,7 @@ namespace Avalonia.Controls.Converters
                 return AvaloniaProperty.UnsetValue;
             }
 
-            if (visiblity == ScrollBarVisibility.Auto)
+            if (visibility == ScrollBarVisibility.Auto)
             {
                 if (extent == viewport)
                 {

src/Avalonia.Controls/DateTimePickers/DatePicker.cs

@@ -2,6 +2,7 @@
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using Avalonia.Interactivity;
 using System;
 using System.Collections.Generic;
@@ -70,7 +71,7 @@ namespace Avalonia.Controls
                 x => x.MonthVisible, (x, v) => x.MonthVisible = v);
 
         /// <summary>
-        /// Defiens the <see cref="YearFormat"/> Property
+        /// Defines the <see cref="YearFormat"/> Property
         /// </summary>
         public static readonly DirectProperty<DatePicker, string> YearFormatProperty =
             AvaloniaProperty.RegisterDirect<DatePicker, string>(nameof(YearFormat), 
@@ -88,7 +89,8 @@ namespace Avalonia.Controls
         /// </summary>
         public static readonly DirectProperty<DatePicker, DateTimeOffset?> SelectedDateProperty =
             AvaloniaProperty.RegisterDirect<DatePicker, DateTimeOffset?>(nameof(SelectedDate), 
-                x => x.SelectedDate, (x, v) => x.SelectedDate = v);
+                x => x.SelectedDate, (x, v) => x.SelectedDate = v,
+                defaultBindingMode: BindingMode.TwoWay);
 
         // Template Items
         private Button _flyoutButton;

src/Avalonia.Controls/DateTimePickers/DateTimePickerPanel.cs

@@ -220,15 +220,15 @@ namespace Avalonia.Controls.Primitives
 
                 if (dy > 0) // Scroll Down
                 {
-                    int numContsToMove = 0;
+                    int numCountsToMove = 0;
                     for (int i = 0; i < children.Count; i++)
                     {
                         if (children[i].Bounds.Bottom - dy < 0)
-                            numContsToMove++;
+                            numCountsToMove++;
                         else
                             break;
                     }
-                    children.MoveRange(0, numContsToMove, children.Count);
+                    children.MoveRange(0, numCountsToMove, children.Count);
 
                     var scrollHeight = _extent.Height - Viewport.Height;
                     if (ShouldLoop && value.Y >= scrollHeight - _extentOne)
@@ -236,15 +236,15 @@ namespace Avalonia.Controls.Primitives
                 }
                 else if (dy < 0) // Scroll Up
                 {
-                    int numContsToMove = 0;
+                    int numCountsToMove = 0;
                     for (int i = children.Count - 1; i >= 0; i--)
                     {
                         if (children[i].Bounds.Top - dy > Bounds.Height)
-                            numContsToMove++;
+                            numCountsToMove++;
                         else
                             break;
                     }
-                    children.MoveRange(children.Count - numContsToMove, numContsToMove, 0);
+                    children.MoveRange(children.Count - numCountsToMove, numCountsToMove, 0);
                     if (ShouldLoop && value.Y < _extentOne)
                         _offset = new Vector(0, value.Y + (_extentOne * 50));
                 }

src/Avalonia.Controls/DateTimePickers/TimePicker.cs

@@ -2,6 +2,7 @@
 using Avalonia.Controls.Primitives;
 using Avalonia.Controls.Shapes;
 using Avalonia.Controls.Templates;
+using Avalonia.Data;
 using System;
 using System.Globalization;
 
@@ -44,7 +45,8 @@ namespace Avalonia.Controls
         /// </summary>
         public static readonly DirectProperty<TimePicker, TimeSpan?> SelectedTimeProperty =
             AvaloniaProperty.RegisterDirect<TimePicker, TimeSpan?>(nameof(SelectedTime),
-                x => x.SelectedTime, (x, v) => x.SelectedTime = v);
+                x => x.SelectedTime, (x, v) => x.SelectedTime = v,
+                defaultBindingMode: BindingMode.TwoWay);
 
         // Template Items
         private TimePickerPresenter _presenter;

src/Avalonia.Controls/DefinitionBase.cs

@@ -35,7 +35,7 @@ namespace Avalonia.Controls
             if (_sharedState == null)
             {
                 //  start with getting SharedSizeGroup value. 
-                //  this property is NOT inhereted which should result in better overall perf.
+                //  this property is NOT inherited which should result in better overall perf.
                 string sharedSizeGroupId = SharedSizeGroup;
                 if (sharedSizeGroupId != null)
                 {
@@ -52,7 +52,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Callback to notify about exitting model tree.
+        /// Callback to notify about exiting model tree.
         /// </summary>
         internal void OnExitParentTree()
         {
@@ -458,7 +458,7 @@ namespace Avalonia.Controls
         private Grid.LayoutTimeSizeType _sizeType;      //  layout-time user size type. it may differ from _userSizeValueCache.UnitType when calculating "to-content"
 
         private double _minSize;                        //  used during measure to accumulate size for "Auto" and "Star" DefinitionBase's
-        private double _measureSize;                    //  size, calculated to be the input contstraint size for Child.Measure
+        private double _measureSize;                    //  size, calculated to be the input constraint size for Child.Measure
         private double _sizeCache;                      //  cache used for various purposes (sorting, caching, etc) during calculations
         private double _offset;                         //  offset of the DefinitionBase from left / top corner (assuming LTR case)
 
@@ -556,7 +556,7 @@ namespace Avalonia.Controls
             }
 
             /// <summary>
-            /// Propogates invalidations for all registered definitions.
+            /// Propagates invalidations for all registered definitions.
             /// Resets its own state.
             /// </summary>
             internal void Invalidate()

src/Avalonia.Controls/Design.cs

@@ -60,6 +60,19 @@ namespace Avalonia.Controls
             return target.GetValue(PreviewWithProperty);
         }
 
+        public static readonly AttachedProperty<IStyle> DesignStyleProperty = AvaloniaProperty
+            .RegisterAttached<Control, IStyle>("DesignStyle", typeof(Design));
+
+        public static void SetDesignStyle(Control control, IStyle value)
+        {
+            control.SetValue(DesignStyleProperty, value);
+        }
+
+        public static IStyle GetDesignStyle(Control control)
+        {
+            return control.GetValue(DesignStyleProperty);
+        }
+
         public static void ApplyDesignModeProperties(Control target, Control source)
         {
             if (source.IsSet(WidthProperty))
@@ -68,6 +81,8 @@ namespace Avalonia.Controls
                 target.Height = source.GetValue(HeightProperty);
             if (source.IsSet(DataContextProperty))
                 target.DataContext = source.GetValue(DataContextProperty);
+            if (source.IsSet(DesignStyleProperty))
+                target.Styles.Add(source.GetValue(DesignStyleProperty));
         }
     }
 }