From 8477d085d098eb877d12d542a80253f89b370653 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wies=C5=82aw=20=C5=A0olt=C3=A9s?= <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 00:17:33 +0100
Subject: [PATCH 01/15] Make grid sizes Auto in scrollbar template

---
 src/Avalonia.Themes.Default/ScrollBar.xaml | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index ae40929573..2f0d48db27 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -3,7 +3,7 @@
         <Setter Property="Template">
             <ControlTemplate>
                 <Border Background="{DynamicResource ThemeControlMidBrush}">
-                    <Grid RowDefinitions="10,*,10">
+                    <Grid RowDefinitions="Auto,*,Auto">
                         <RepeatButton Name="PART_LineUpButton"
                                       Classes="repeat"
                                       Grid.Row="0"
@@ -58,7 +58,7 @@
         <Setter Property="Template">
             <ControlTemplate>
                 <Border Background="{DynamicResource ThemeControlMidBrush}">
-                    <Grid ColumnDefinitions="10,*,10">
+                    <Grid ColumnDefinitions="Auto,*,Auto">
                         <RepeatButton Name="PART_LineUpButton"
                                       Classes="repeat"
                                       Grid.Row="0"

From c0a86be6bf75d606e227066edfd4a9afca0864b3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wies=C5=82aw=20=C5=A0olt=C3=A9s?= <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 00:26:13 +0100
Subject: [PATCH 02/15] Added ScrollBar size resources

---
 src/Avalonia.Themes.Default/Accents/BaseDark.xaml  | 3 +++
 src/Avalonia.Themes.Default/Accents/BaseLight.xaml | 3 +++
 src/Avalonia.Themes.Default/ScrollBar.xaml         | 8 ++++----
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Themes.Default/Accents/BaseDark.xaml b/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
index 95b351b148..2a20892869 100644
--- a/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
+++ b/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
@@ -52,5 +52,8 @@
         <sys:Double x:Key="FontSizeSmall">10</sys:Double>
         <sys:Double x:Key="FontSizeNormal">12</sys:Double>
         <sys:Double x:Key="FontSizeLarge">16</sys:Double>
+
+        <sys:Double x:Key="ScrollBarWidth">10</sys:Double>
+        <sys:Double x:Key="ScrollBarHeight">10</sys:Double>
     </Style.Resources>
 </Style>
diff --git a/src/Avalonia.Themes.Default/Accents/BaseLight.xaml b/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
index 4d1c4b1ab0..e94653a3d6 100644
--- a/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
+++ b/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
@@ -52,5 +52,8 @@
         <sys:Double x:Key="FontSizeSmall">10</sys:Double>
         <sys:Double x:Key="FontSizeNormal">12</sys:Double>
         <sys:Double x:Key="FontSizeLarge">16</sys:Double>
+
+        <sys:Double x:Key="ScrollBarWidth">10</sys:Double>
+        <sys:Double x:Key="ScrollBarHeight">10</sys:Double>
     </Style.Resources>
 </Style>
diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index 2f0d48db27..e22a62ee7f 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -54,7 +54,7 @@
     </Style>
     <Style Selector="ScrollBar:horizontal">
         <Setter Property="Height"
-                Value="10" />
+                Value="{DynamicResource ScrollBarHeight}" />
         <Setter Property="Template">
             <ControlTemplate>
                 <Border Background="{DynamicResource ThemeControlMidBrush}">
@@ -109,15 +109,15 @@
     </Style>
     <Style Selector="ScrollBar:horizontal /template/ Thumb#thumb">
         <Setter Property="MinWidth"
-                Value="10" />
+                Value="{DynamicResource ScrollBarWidth}" />
     </Style>
     <Style Selector="ScrollBar:vertical">
         <Setter Property="Width"
-                Value="10" />
+                Value="{DynamicResource ScrollBarWidth}" />
     </Style>
     <Style Selector="ScrollBar:vertical /template/ Thumb#thumb">
         <Setter Property="MinHeight"
-                Value="10" />
+                Value="{DynamicResource ScrollBarHeight}" />
     </Style>
     <Style Selector="ScrollBar /template/ RepeatButton.repeat">
         <Setter Property="Padding"

From 1d8ea08d0b65f5c71102e396401ad7c0cf76651b Mon Sep 17 00:00:00 2001
From: wieslawsoltes <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 13:06:33 +0000
Subject: [PATCH 03/15] Try to fix tests

---
 tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
index b8b9b69b6c..802d83501e 100644
--- a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
@@ -113,17 +113,17 @@ namespace Avalonia.Layout.UnitTests
                 Assert.Single(presenters);
 
                 var presenter = presenters[0];
-                Assert.Equal(new Size(190, 190), presenter.Bounds.Size);
+                Assert.Equal(new Size(196, 196), presenter.Bounds.Size);
 
                 var horzScroll = scrollBars.Single(x => x.Orientation == Orientation.Horizontal);
                 var vertScroll = scrollBars.Single(x => x.Orientation == Orientation.Vertical);
 
                 Assert.True(horzScroll.IsVisible);
                 Assert.True(vertScroll.IsVisible);
-                Assert.Equal(new Size(190, 10), horzScroll.Bounds.Size);
-                Assert.Equal(new Size(10, 190), vertScroll.Bounds.Size);
-                Assert.Equal(new Point(0, 190), Position(horzScroll));
-                Assert.Equal(new Point(190, 0), Position(vertScroll));
+                Assert.Equal(new Size(196, 10), horzScroll.Bounds.Size);
+                Assert.Equal(new Size(10, 196), vertScroll.Bounds.Size);
+                Assert.Equal(new Point(0, 196), Position(horzScroll));
+                Assert.Equal(new Point(196, 0), Position(vertScroll));
             }
         }
 

From bfc748bd3fc9c47b658770a086a67dbee3735f89 Mon Sep 17 00:00:00 2001
From: wieslawsoltes <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 13:58:19 +0000
Subject: [PATCH 04/15] Format setters

---
 src/Avalonia.Themes.Default/ScrollBar.xaml | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index e22a62ee7f..982af43587 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -53,8 +53,7 @@
         </Setter>
     </Style>
     <Style Selector="ScrollBar:horizontal">
-        <Setter Property="Height"
-                Value="{DynamicResource ScrollBarHeight}" />
+        <Setter Property="Height" Value="{DynamicResource ScrollBarHeight}" />
         <Setter Property="Template">
             <ControlTemplate>
                 <Border Background="{DynamicResource ThemeControlMidBrush}">
@@ -108,22 +107,17 @@
         </Setter>
     </Style>
     <Style Selector="ScrollBar:horizontal /template/ Thumb#thumb">
-        <Setter Property="MinWidth"
-                Value="{DynamicResource ScrollBarWidth}" />
+        <Setter Property="MinWidth" Value="{DynamicResource ScrollBarWidth}" />
     </Style>
     <Style Selector="ScrollBar:vertical">
-        <Setter Property="Width"
-                Value="{DynamicResource ScrollBarWidth}" />
+        <Setter Property="Width" Value="{DynamicResource ScrollBarWidth}" />
     </Style>
     <Style Selector="ScrollBar:vertical /template/ Thumb#thumb">
-        <Setter Property="MinHeight"
-                Value="{DynamicResource ScrollBarHeight}" />
+        <Setter Property="MinHeight" Value="{DynamicResource ScrollBarHeight}" />
     </Style>
     <Style Selector="ScrollBar /template/ RepeatButton.repeat">
-        <Setter Property="Padding"
-                Value="2" />
-        <Setter Property="BorderThickness"
-                Value="0" />
+        <Setter Property="Padding" Value="2" />
+        <Setter Property="BorderThickness" Value="0" />
     </Style>
     <Style Selector="ScrollBar /template/ RepeatButton.repeattrack">
         <Setter Property="Template">

From 5d8c6beed00d9b14369a1fbe325bdc093f5ec865 Mon Sep 17 00:00:00 2001
From: wieslawsoltes <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 14:11:18 +0000
Subject: [PATCH 05/15] Fix tests

---
 tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
index 802d83501e..d99d05facb 100644
--- a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
@@ -120,8 +120,8 @@ namespace Avalonia.Layout.UnitTests
 
                 Assert.True(horzScroll.IsVisible);
                 Assert.True(vertScroll.IsVisible);
-                Assert.Equal(new Size(196, 10), horzScroll.Bounds.Size);
-                Assert.Equal(new Size(10, 196), vertScroll.Bounds.Size);
+                Assert.Equal(new Size(196, 4), horzScroll.Bounds.Size);
+                Assert.Equal(new Size(4, 196), vertScroll.Bounds.Size);
                 Assert.Equal(new Point(0, 196), Position(horzScroll));
                 Assert.Equal(new Point(196, 0), Position(vertScroll));
             }

From 29cef8a7deb1075e1fc5394701f33175d118bf37 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wies=C5=82aw=20=C5=A0olt=C3=A9s?= <wieslaw.soltes@gmail.com>
Date: Wed, 14 Nov 2018 19:58:59 +0100
Subject: [PATCH 06/15] Update FullLayoutTests.cs

---
 tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
index d99d05facb..800366bc09 100644
--- a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
@@ -98,6 +98,9 @@ namespace Avalonia.Layout.UnitTests
                     }
                 };
 
+                window.Resources["ScrollBarWidth"] = 10.0;
+                window.Resources["ScrollBarHeight"] = 10.0;
+
                 window.Show();
                 window.LayoutManager.ExecuteInitialLayoutPass(window);
 
@@ -113,17 +116,17 @@ namespace Avalonia.Layout.UnitTests
                 Assert.Single(presenters);
 
                 var presenter = presenters[0];
-                Assert.Equal(new Size(196, 196), presenter.Bounds.Size);
+                Assert.Equal(new Size(190, 190), presenter.Bounds.Size);
 
                 var horzScroll = scrollBars.Single(x => x.Orientation == Orientation.Horizontal);
                 var vertScroll = scrollBars.Single(x => x.Orientation == Orientation.Vertical);
 
                 Assert.True(horzScroll.IsVisible);
                 Assert.True(vertScroll.IsVisible);
-                Assert.Equal(new Size(196, 4), horzScroll.Bounds.Size);
-                Assert.Equal(new Size(4, 196), vertScroll.Bounds.Size);
-                Assert.Equal(new Point(0, 196), Position(horzScroll));
-                Assert.Equal(new Point(196, 0), Position(vertScroll));
+                Assert.Equal(new Size(190, 10), horzScroll.Bounds.Size);
+                Assert.Equal(new Size(10, 190), vertScroll.Bounds.Size);
+                Assert.Equal(new Point(0, 190), Position(horzScroll));
+                Assert.Equal(new Point(190, 0), Position(vertScroll));
             }
         }
 

From 338fe1d5eb18c6820a1b1196e2e190c3ce57ebef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wies=C5=82aw=20=C5=A0olt=C3=A9s?= <wieslaw.soltes@gmail.com>
Date: Sun, 18 Nov 2018 14:11:55 +0100
Subject: [PATCH 07/15] Use thickness instead of width and height

---
 src/Avalonia.Themes.Default/Accents/BaseDark.xaml  | 3 +--
 src/Avalonia.Themes.Default/Accents/BaseLight.xaml | 3 +--
 src/Avalonia.Themes.Default/ScrollBar.xaml         | 8 ++++----
 tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs | 3 +--
 4 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/src/Avalonia.Themes.Default/Accents/BaseDark.xaml b/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
index 2a20892869..e9d710b3f0 100644
--- a/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
+++ b/src/Avalonia.Themes.Default/Accents/BaseDark.xaml
@@ -53,7 +53,6 @@
         <sys:Double x:Key="FontSizeNormal">12</sys:Double>
         <sys:Double x:Key="FontSizeLarge">16</sys:Double>
 
-        <sys:Double x:Key="ScrollBarWidth">10</sys:Double>
-        <sys:Double x:Key="ScrollBarHeight">10</sys:Double>
+        <sys:Double x:Key="ScrollBarThickness">10</sys:Double>
     </Style.Resources>
 </Style>
diff --git a/src/Avalonia.Themes.Default/Accents/BaseLight.xaml b/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
index e94653a3d6..c40305151e 100644
--- a/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
+++ b/src/Avalonia.Themes.Default/Accents/BaseLight.xaml
@@ -53,7 +53,6 @@
         <sys:Double x:Key="FontSizeNormal">12</sys:Double>
         <sys:Double x:Key="FontSizeLarge">16</sys:Double>
 
-        <sys:Double x:Key="ScrollBarWidth">10</sys:Double>
-        <sys:Double x:Key="ScrollBarHeight">10</sys:Double>
+        <sys:Double x:Key="ScrollBarThickness">10</sys:Double>
     </Style.Resources>
 </Style>
diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index 982af43587..2cb8ce2d24 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -53,7 +53,7 @@
         </Setter>
     </Style>
     <Style Selector="ScrollBar:horizontal">
-        <Setter Property="Height" Value="{DynamicResource ScrollBarHeight}" />
+        <Setter Property="Height" Value="{DynamicResource ScrollBarThickness}" />
         <Setter Property="Template">
             <ControlTemplate>
                 <Border Background="{DynamicResource ThemeControlMidBrush}">
@@ -107,13 +107,13 @@
         </Setter>
     </Style>
     <Style Selector="ScrollBar:horizontal /template/ Thumb#thumb">
-        <Setter Property="MinWidth" Value="{DynamicResource ScrollBarWidth}" />
+        <Setter Property="MinWidth" Value="{DynamicResource ScrollBarThickness}" />
     </Style>
     <Style Selector="ScrollBar:vertical">
-        <Setter Property="Width" Value="{DynamicResource ScrollBarWidth}" />
+        <Setter Property="Width" Value="{DynamicResource ScrollBarThickness}" />
     </Style>
     <Style Selector="ScrollBar:vertical /template/ Thumb#thumb">
-        <Setter Property="MinHeight" Value="{DynamicResource ScrollBarHeight}" />
+        <Setter Property="MinHeight" Value="{DynamicResource ScrollBarThickness}" />
     </Style>
     <Style Selector="ScrollBar /template/ RepeatButton.repeat">
         <Setter Property="Padding" Value="2" />
diff --git a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
index 92fc08b335..ffdb146eec 100644
--- a/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
+++ b/tests/Avalonia.Layout.UnitTests/FullLayoutTests.cs
@@ -99,8 +99,7 @@ namespace Avalonia.Layout.UnitTests
                     }
                 };
 
-                window.Resources["ScrollBarWidth"] = 10.0;
-                window.Resources["ScrollBarHeight"] = 10.0;
+                window.Resources["ScrollBarThickness"] = 10.0;
 
                 window.Show();
                 window.LayoutManager.ExecuteInitialLayoutPass(window);

From 4f049cf1558618bafebbd85188b254baf76eba41 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 15:39:36 +0300
Subject: [PATCH 08/15] Allow GC to collect reused framebuffer, that's better
 than AccessViolationException from render thread

---
 src/Windows/Avalonia.Win32/FramebufferManager.cs | 7 +------
 src/Windows/Avalonia.Win32/WindowImpl.cs         | 3 +--
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/Windows/Avalonia.Win32/FramebufferManager.cs b/src/Windows/Avalonia.Win32/FramebufferManager.cs
index c910703181..87c5a1bb02 100644
--- a/src/Windows/Avalonia.Win32/FramebufferManager.cs
+++ b/src/Windows/Avalonia.Win32/FramebufferManager.cs
@@ -5,7 +5,7 @@ using Avalonia.Win32.Interop;
 
 namespace Avalonia.Win32
 {
-    class FramebufferManager : IFramebufferPlatformSurface, IDisposable
+    class FramebufferManager : IFramebufferPlatformSurface
     {
         private readonly IntPtr _hwnd;
         private WindowFramebuffer _fb;
@@ -29,10 +29,5 @@ namespace Avalonia.Win32
             }
             return _fb;
         }
-
-        public void Dispose()
-        {
-            _fb?.Deallocate();
-        }
     }
 }
diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index 4c08e985cd..18f0696cd8 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -13,6 +13,7 @@ using Avalonia.Input.Raw;
 using Avalonia.OpenGL;
 using Avalonia.Platform;
 using Avalonia.Rendering;
+using Avalonia.Threading;
 using Avalonia.Win32.Input;
 using Avalonia.Win32.Interop;
 using static Avalonia.Win32.Interop.UnmanagedMethods;
@@ -234,8 +235,6 @@ namespace Avalonia.Win32
 
         public void Dispose()
         {
-            _framebuffer?.Dispose();
-            _framebuffer = null;
             if (_hwnd != IntPtr.Zero)
             {
                 UnmanagedMethods.DestroyWindow(_hwnd);

From d1e304741019b4796435994b8b27151b36e502d8 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 15:40:46 +0300
Subject: [PATCH 09/15] Don't be noisy about just-in-case Dispose call on
 disposed object on finalizer thread

---
 src/Shared/PlatformSupport/StandardRuntimePlatform.cs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/Shared/PlatformSupport/StandardRuntimePlatform.cs b/src/Shared/PlatformSupport/StandardRuntimePlatform.cs
index 186c55d9eb..8a5a725594 100644
--- a/src/Shared/PlatformSupport/StandardRuntimePlatform.cs
+++ b/src/Shared/PlatformSupport/StandardRuntimePlatform.cs
@@ -89,9 +89,11 @@ namespace Avalonia.Shared.PlatformSupport
 #if DEBUG
                 if (Thread.CurrentThread.ManagedThreadId == GCThread?.ManagedThreadId)
                 {
-                    Console.Error.WriteLine("Native blob disposal from finalizer thread\nBacktrace: "
-                                            + Environment.StackTrace
-                                            + "\n\nBlob created by " + _backtrace);
+                    lock(_lock)
+                        if (!IsDisposed)
+                            Console.Error.WriteLine("Native blob disposal from finalizer thread\nBacktrace: "
+                                                    + Environment.StackTrace
+                                                    + "\n\nBlob created by " + _backtrace);
                 }
 #endif
                 DoDispose();

From 31b6a0d16ca4efbc8cad1b06556e83a17b5db6f2 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 16:02:40 +0300
Subject: [PATCH 10/15] Wait for scene to be consumed before producing a new
 one. Fixes TONS of variour rendering  artifacts

---
 .../Rendering/DeferredRenderer.cs             | 40 +++++++++++++++----
 1 file changed, 32 insertions(+), 8 deletions(-)

diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index a268eff78a..a45ea62cd2 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -37,6 +37,7 @@ namespace Avalonia.Rendering
         private DisplayDirtyRects _dirtyRectsDisplay = new DisplayDirtyRects();
         private IRef<IDrawOperation> _currentDraw;
         private readonly IDeferredRendererLock _lock;
+        private readonly object _sceneLock = new object();
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DeferredRenderer"/> class.
@@ -172,7 +173,8 @@ namespace Avalonia.Rendering
             }
         }
 
-        bool IRenderLoopTask.NeedsUpdate => _dirty == null || _dirty.Count > 0;
+        bool NeedsUpdate => _dirty == null || _dirty.Count > 0;
+        bool IRenderLoopTask.NeedsUpdate => NeedsUpdate;
 
         void IRenderLoopTask.Update(TimeSpan time) => UpdateScene();
 
@@ -197,19 +199,23 @@ namespace Avalonia.Rendering
 
         internal void UnitTestUpdateScene() => UpdateScene();
 
-        internal void UnitTestRender() => Render(_scene.Item, false);
+        internal void UnitTestRender() => Render(_scene.Item, false, false);
 
         private void Render(bool forceComposite)
         {
             using (var l = _lock.TryLock())
                 if (l != null)
-                    using (var scene = _scene?.Clone())
+                {
+                    bool reRun = false;
+                    do
                     {
-                        Render(scene?.Item, forceComposite);
-                    }
+                        using (var scene = _scene?.Clone())
+                            reRun = Render(scene?.Item, forceComposite, reRun);
+                    } while (reRun);
+                }
         }
-        
-        private void Render(Scene scene, bool forceComposite)
+       
+        private bool Render(Scene scene, bool forceComposite, bool reUpdating)
         {
             bool renderOverlay = DrawDirtyRects || DrawFps;
             bool composite = false;
@@ -242,7 +248,18 @@ namespace Avalonia.Rendering
                             SaveDebugFrames(scene.Generation);
                         }
 
-                        _lastSceneId = scene.Generation;
+                        lock (_sceneLock)
+                            _lastSceneId = scene.Generation;
+
+                        // We have consumed the previously available scene, but there might be some dirty 
+                        // rects since the last update. *If* we are on UI thread, we can force immediate scene
+                        // rebuild before rendering anything on-screen
+                        // By returning true we indicate that this method should be called again
+                        if (!reUpdating && Dispatcher.UIThread.CheckAccess() && NeedsUpdate)
+                        {
+                            UpdateScene();
+                            return true;
+                        }
 
                         composite = true;
                     }
@@ -268,6 +285,8 @@ namespace Avalonia.Rendering
                 RenderTarget?.Dispose();
                 RenderTarget = null;
             }
+
+            return false;
         }
 
         private void Render(IDrawingContextImpl context, VisualNode node, IVisual layer, Rect clipBounds)
@@ -405,6 +424,11 @@ namespace Avalonia.Rendering
         private void UpdateScene()
         {
             Dispatcher.UIThread.VerifyAccess();
+            lock (_sceneLock)
+            {
+                if (_scene?.Item.Generation > _lastSceneId)
+                    return;
+            }
             if (_root.IsVisible)
             {
                 var sceneRef = RefCountable.Create(_scene?.Item.CloneScene() ?? new Scene(_root));

From 02200eb4d3d2e3ef38c0390212214f08c52b01b3 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 16:12:47 +0300
Subject: [PATCH 11/15] Use proper locks for _scene manipulation

---
 .../Rendering/DeferredRenderer.cs             | 33 ++++++++++++++-----
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index a45ea62cd2..cbf472426f 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -119,8 +119,13 @@ namespace Avalonia.Rendering
         /// </summary>
         public void Dispose()
         {
-            var scene = Interlocked.Exchange(ref _scene, null);
-            scene?.Dispose();
+            lock (_sceneLock)
+            {
+                var scene = _scene;
+                _scene = null;
+                scene?.Dispose();
+            }
+
             Stop();
 
             Layers.Clear();
@@ -135,7 +140,8 @@ namespace Avalonia.Rendering
                 // When unit testing the renderLoop may be null, so update the scene manually.
                 UpdateScene();
             }
-
+            //It's safe to access _scene here without a lock since
+            //it's only changed from UI thread which we are currently on
             return _scene?.Item.HitTest(p, root, filter) ?? Enumerable.Empty<IVisual>();
         }
 
@@ -209,7 +215,10 @@ namespace Avalonia.Rendering
                     bool reRun = false;
                     do
                     {
-                        using (var scene = _scene?.Clone())
+                        IRef<Scene> scene;
+                        lock (_sceneLock)
+                            scene = _scene?.Clone();
+                        using (scene)
                             reRun = Render(scene?.Item, forceComposite, reRun);
                     } while (reRun);
                 }
@@ -447,15 +456,23 @@ namespace Avalonia.Rendering
                     }
                 }
 
-                var oldScene = Interlocked.Exchange(ref _scene, sceneRef);
-                oldScene?.Dispose();
+                lock (_sceneLock)
+                {
+                    var oldScene = _scene;
+                    _scene = sceneRef;
+                    oldScene?.Dispose();
+                }
 
                 _dirty.Clear();
             }
             else
             {
-                var oldScene = Interlocked.Exchange(ref _scene, null);
-                oldScene?.Dispose();
+                lock (_sceneLock)
+                {
+                    var oldScene = _scene;
+                    _scene = null;
+                    oldScene?.Dispose();
+                }
             }
         }
 

From 36915d6c9453260105de31807d75984cc772fe38 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 16:57:34 +0300
Subject: [PATCH 12/15] Reworked rendering

---
 .../Rendering/DeferredRenderer.cs             | 146 +++++++++---------
 1 file changed, 76 insertions(+), 70 deletions(-)

diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index cbf472426f..d2852786c6 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -205,99 +205,105 @@ namespace Avalonia.Rendering
 
         internal void UnitTestUpdateScene() => UpdateScene();
 
-        internal void UnitTestRender() => Render(_scene.Item, false, false);
+        internal void UnitTestRender() => Render(false);
 
         private void Render(bool forceComposite)
         {
             using (var l = _lock.TryLock())
-                if (l != null)
-                {
-                    bool reRun = false;
-                    do
-                    {
-                        IRef<Scene> scene;
-                        lock (_sceneLock)
-                            scene = _scene?.Clone();
-                        using (scene)
-                            reRun = Render(scene?.Item, forceComposite, reRun);
-                    } while (reRun);
-                }
-        }
-       
-        private bool Render(Scene scene, bool forceComposite, bool reUpdating)
-        {
-            bool renderOverlay = DrawDirtyRects || DrawFps;
-            bool composite = false;
-
-            if (RenderTarget == null)
             {
-                RenderTarget = ((IRenderRoot)_root).CreateRenderTarget();
-            }
-
-            if (renderOverlay)
-            {
-                _dirtyRectsDisplay.Tick();
-            }
+                if (l == null)
+                    return;
 
-            try
-            {
-                if (scene != null && scene.Size != Size.Empty)
+                IDrawingContextImpl context = null;
+                try
                 {
-                    IDrawingContextImpl context = null;
-
-                    if (scene.Generation != _lastSceneId)
+                    try
                     {
-                        context = RenderTarget.CreateDrawingContext(this);
-                        Layers.Update(scene, context);
-
-                        RenderToLayers(scene);
-
-                        if (DebugFramesPath != null)
+                        IDrawingContextImpl GetContext()
                         {
-                            SaveDebugFrames(scene.Generation);
-                        }
+                            if (context != null)
+                                return context;
+                            if (RenderTarget == null)
+                                RenderTarget = ((IRenderRoot)_root).CreateRenderTarget();
+                            return context = RenderTarget.CreateDrawingContext(this);
 
-                        lock (_sceneLock)
-                            _lastSceneId = scene.Generation;
+                        }
 
-                        // We have consumed the previously available scene, but there might be some dirty 
-                        // rects since the last update. *If* we are on UI thread, we can force immediate scene
-                        // rebuild before rendering anything on-screen
-                        // By returning true we indicate that this method should be called again
-                        if (!reUpdating && Dispatcher.UIThread.CheckAccess() && NeedsUpdate)
+                        var (scene, updated) = UpdateRenderLayersAndConsumeSceneIfNeeded(GetContext);
+                        using (scene)
                         {
-                            UpdateScene();
-                            return true;
+                            var overlay = DrawDirtyRects || DrawFps;
+                            if (DrawDirtyRects)
+                                _dirtyRectsDisplay.Tick();
+                            if (overlay)
+                                RenderOverlay(scene.Item, GetContext());
+                            if (updated || forceComposite || overlay)
+                                RenderComposite(scene.Item, GetContext());
                         }
-
-                        composite = true;
                     }
-
-                    if (renderOverlay)
+                    finally
                     {
-                        context = context ?? RenderTarget.CreateDrawingContext(this);
-                        RenderOverlay(scene, context);
-                        RenderComposite(scene, context);
+                        context?.Dispose();
                     }
-                    else if (composite || forceComposite)
+                }
+                catch (RenderTargetCorruptedException ex)
+                {
+                    Logging.Logger.Information("Renderer", this, "Render target was corrupted. Exception: {0}", ex);
+                    RenderTarget?.Dispose();
+                    RenderTarget = null;
+                }
+            }
+        }
+
+        private (IRef<Scene> scene, bool updated) UpdateRenderLayersAndConsumeSceneIfNeeded(Func<IDrawingContextImpl> contextFactory,
+            bool recursiveCall = false)
+        {
+            IRef<Scene> sceneRef;
+            lock (_sceneLock)
+                sceneRef = _scene?.Clone();
+            if (sceneRef == null)
+                return (null, false);
+            using (sceneRef)
+            {
+                var scene = sceneRef.Item;
+                if (scene.Generation != _lastSceneId)
+                {
+                    var context = contextFactory();
+                    Layers.Update(scene, context);
+
+                    RenderToLayers(scene);
+
+                    if (DebugFramesPath != null)
                     {
-                        context = context ?? RenderTarget.CreateDrawingContext(this);
-                        RenderComposite(scene, context);
+                        SaveDebugFrames(scene.Generation);
                     }
 
-                    context?.Dispose();
+                    lock (_sceneLock)
+                        _lastSceneId = scene.Generation;
+
+
+                    // We have consumed the previously available scene, but there might be some dirty 
+                    // rects since the last update. *If* we are on UI thread, we can force immediate scene
+                    // rebuild before rendering anything on-screen
+                    // We are calling the same method recursively here 
+                    if (!recursiveCall && Dispatcher.UIThread.CheckAccess() && NeedsUpdate)
+                    {
+                        UpdateScene();
+                        var (rs, _) = UpdateRenderLayersAndConsumeSceneIfNeeded(contextFactory, true);
+                        return (rs, true);
+                    }
+                    
+                    // Indicate that we have updated the layers
+                    return (sceneRef.Clone(), true);
                 }
+                
+                // Just return scene, layers weren't updated
+                return (sceneRef.Clone(), false);
             }
-            catch (RenderTargetCorruptedException ex)
-            {
-                Logging.Logger.Information("Renderer", this, "Render target was corrupted. Exception: {0}", ex);
-                RenderTarget?.Dispose();
-                RenderTarget = null;
-            }
-
-            return false;
+            
         }
 
+
         private void Render(IDrawingContextImpl context, VisualNode node, IVisual layer, Rect clipBounds)
         {
             if (layer == null || node.LayerRoot == layer)

From b84069b27fae6e6158b452336ad6a1ace8349068 Mon Sep 17 00:00:00 2001
From: Benedikt Schroeder <benedikt.schroeder@outlook.de>
Date: Mon, 19 Nov 2018 15:30:06 +0100
Subject: [PATCH 13/15] Remove redundant scrollviewer from default control
 template

---
 src/Avalonia.Themes.Default/TabControl.xaml | 41 +++++++++------------
 1 file changed, 17 insertions(+), 24 deletions(-)

diff --git a/src/Avalonia.Themes.Default/TabControl.xaml b/src/Avalonia.Themes.Default/TabControl.xaml
index 969887b38e..28de70ebb6 100644
--- a/src/Avalonia.Themes.Default/TabControl.xaml
+++ b/src/Avalonia.Themes.Default/TabControl.xaml
@@ -3,8 +3,6 @@
         <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
         <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
         <Setter Property="Padding" Value="4"/>
-        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto"/>
-        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Auto"/>
         <Setter Property="VerticalContentAlignment" Value="Stretch"/>
         <Setter Property="HorizontalContentAlignment" Value="Stretch"/>
         <Setter Property="Template">
@@ -16,28 +14,23 @@
                     Background="{TemplateBinding Background}"
                     HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                     VerticalAlignment="{TemplateBinding VerticalAlignment}">
-                    <ScrollViewer
-                        Name="PART_ScrollViewer"
-                        HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                        VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
-                        <DockPanel>
-                            <ItemsPresenter
-                                Name="PART_ItemsPresenter"
-                                Items="{TemplateBinding Items}"
-                                ItemsPanel="{TemplateBinding ItemsPanel}"
-                                ItemTemplate="{TemplateBinding ItemTemplate}"
-                                MemberSelector="{TemplateBinding MemberSelector}"                     >
-                            </ItemsPresenter>
-                            <ContentPresenter
-                                Name="PART_Content"
-                                Margin="{TemplateBinding Padding}"
-                                HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
-                                VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
-                                Content="{TemplateBinding SelectedContent}"
-                                ContentTemplate="{TemplateBinding SelectedContentTemplate}">
-                            </ContentPresenter>
-                        </DockPanel>
-                    </ScrollViewer>
+                    <DockPanel>
+                        <ItemsPresenter
+                            Name="PART_ItemsPresenter"
+                            Items="{TemplateBinding Items}"
+                            ItemsPanel="{TemplateBinding ItemsPanel}"
+                            ItemTemplate="{TemplateBinding ItemTemplate}"
+                            MemberSelector="{TemplateBinding MemberSelector}"                     >
+                        </ItemsPresenter>
+                        <ContentPresenter
+                            Name="PART_Content"
+                            Margin="{TemplateBinding Padding}"
+                            HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                            VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                            Content="{TemplateBinding SelectedContent}"
+                            ContentTemplate="{TemplateBinding SelectedContentTemplate}">
+                        </ContentPresenter>
+                    </DockPanel>
                 </Border>
             </ControlTemplate>
         </Setter>

From 2be6390683240a38c10442d8b54f49aaf78f52b1 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 17:38:22 +0300
Subject: [PATCH 14/15] Fixed tests

---
 .../Rendering/DeferredRendererTests_HitTesting.cs             | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
index a53809a029..ab5f5f37f7 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/DeferredRendererTests_HitTesting.cs
@@ -405,7 +405,8 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                 root.Renderer = new DeferredRenderer(root, null);
                 root.Measure(Size.Infinity);
                 root.Arrange(new Rect(container.DesiredSize));
-
+                
+                root.Renderer.Paint(Rect.Empty);
                 var result = root.Renderer.HitTest(new Point(50, 150), root, null).First();
 
                 Assert.Equal(item1, result);
@@ -421,6 +422,7 @@ namespace Avalonia.Visuals.UnitTests.Rendering
                 container.InvalidateArrange();
                 container.Arrange(new Rect(container.DesiredSize));
 
+                root.Renderer.Paint(Rect.Empty);
                 result = root.Renderer.HitTest(new Point(50, 150), root, null).First();
                 Assert.Equal(item2, result);
 

From 5e698a4ab20545ca0409630188bdc1491570ab72 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Mon, 19 Nov 2018 18:13:39 +0300
Subject: [PATCH 15/15] Fixed other tests

---
 src/Avalonia.Visuals/Rendering/DeferredRenderer.cs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
index d2852786c6..b48efaa34e 100644
--- a/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
+++ b/src/Avalonia.Visuals/Rendering/DeferredRenderer.cs
@@ -85,6 +85,7 @@ namespace Avalonia.Rendering
             RenderTarget = renderTarget;
             _sceneBuilder = sceneBuilder ?? new SceneBuilder();
             Layers = new RenderLayers();
+            _lock = new ManagedDeferredRendererLock();
         }
 
         /// <inheritdoc/>