From e7c1c3dbecb85ac86af782677c62db99309bf34a Mon Sep 17 00:00:00 2001
From: Robin Dostal <robinxan@gmail.com>
Date: Mon, 14 Dec 2020 18:00:05 +0100
Subject: [PATCH 01/23] More reliable pixendensitydetection under Xorg/Randr

Physical dimensions are parsed from the monitors EDID instead of Randr.
GuessPixelDensity locks to fixed values, caps at 2 and returns 1 if the supplied
dimensions are unreasonable.
---
 src/Avalonia.X11/X11Atoms.cs   |  2 +
 src/Avalonia.X11/X11Screens.cs | 81 +++++++++++++++++++++++++---------
 src/Avalonia.X11/XLib.cs       |  7 +++
 3 files changed, 70 insertions(+), 20 deletions(-)

diff --git a/src/Avalonia.X11/X11Atoms.cs b/src/Avalonia.X11/X11Atoms.cs
index 32f1822e51..137757b9cf 100644
--- a/src/Avalonia.X11/X11Atoms.cs
+++ b/src/Avalonia.X11/X11Atoms.cs
@@ -114,6 +114,8 @@ namespace Avalonia.X11
         public readonly IntPtr XA_WM_CLASS = (IntPtr)67;
         public readonly IntPtr XA_WM_TRANSIENT_FOR = (IntPtr)68;
 
+        public readonly IntPtr RR_PROPERTY_RANDR_EDID = (IntPtr)82;
+
         public readonly IntPtr WM_PROTOCOLS;
         public readonly IntPtr WM_DELETE_WINDOW;
         public readonly IntPtr WM_TAKE_FOCUS;
diff --git a/src/Avalonia.X11/X11Screens.cs b/src/Avalonia.X11/X11Screens.cs
index af6d2674b6..df1b2b7312 100644
--- a/src/Avalonia.X11/X11Screens.cs
+++ b/src/Avalonia.X11/X11Screens.cs
@@ -82,6 +82,39 @@ namespace Avalonia.X11
                     _cache = null;
             }
 
+            private unsafe Size? GetPhysicalMonitorSizeFromEDID(IntPtr rrOutput)
+            {
+                if(rrOutput == IntPtr.Zero)
+                    return null;
+                var output = Marshal.ReadInt64(rrOutput);
+                var properties = XRRListOutputProperties(_x11.Display,output, out int propertyCount);
+                var hasEDID = false;
+                for(var pc = 0; pc < propertyCount; pc++)
+                {
+                    if(properties[pc] == _x11.Atoms.RR_PROPERTY_RANDR_EDID)
+                        hasEDID = true;
+                }
+                if(!hasEDID)
+                    return null;
+                XRRGetOutputProperty(_x11.Display, output, _x11.Atoms.RR_PROPERTY_RANDR_EDID, 0, 128, false, false, _x11.Atoms.AnyPropertyType, out int actualType, out int actualFormat, out int nItems, out _, out IntPtr prop);
+                if(actualType != 19) // XA_INTEGER
+                    return null;
+                if(actualFormat != 8)
+                    return null;
+
+                var edid = new byte[nItems];
+                Marshal.Copy(prop,edid,0,nItems);
+                XFree(prop);
+                XFree(new IntPtr(properties));
+                if(edid.Length < 22)
+                    return null;
+                var width = edid[21];
+                var height = edid[22];
+                if(width == 0 && height == 0)
+                    return null;
+                return new Size(width * 10, height * 10);
+            }
+
             public unsafe X11Screen[] Screens
             {
                 get
@@ -97,24 +130,13 @@ namespace Avalonia.X11
                         var namePtr = XGetAtomName(_x11.Display, mon.Name);
                         var name = Marshal.PtrToStringAnsi(namePtr);
                         XFree(namePtr);
-
+                        var bounds = new PixelRect(mon.X, mon.Y, mon.Width, mon.Height);
                         var density = 1d;
-                        if (_settings.NamedScaleFactors?.TryGetValue(name, out density) != true)
-                        {
-                            if (mon.MWidth == 0)
-                                density = 1;
-                            else
-                                density = X11Screen.GuessPixelDensity(mon.Width, mon.MWidth);
-                        }
-
+                        var pSize = GetPhysicalMonitorSizeFromEDID(mon.Outputs);
+                        if (_settings.NamedScaleFactors?.TryGetValue(name, out  density) != true && pSize != null)
+                            density = X11Screen.GuessPixelDensity(bounds, pSize.Value);
                         density *= _settings.GlobalScaleFactor;
-                        
-                        var bounds = new PixelRect(mon.X, mon.Y, mon.Width, mon.Height);
-                        screens[c] = new X11Screen(bounds, 
-                            mon.Primary != 0, 
-                            name,
-                            (mon.MWidth == 0 || mon.MHeight == 0) ? (Size?)null : new Size(mon.MWidth, mon.MHeight),
-                            density);
+                        screens[c] = new X11Screen(bounds, mon.Primary != 0, name, pSize, density);
                     }
                     
                     XFree(new IntPtr(monitors));
@@ -163,7 +185,6 @@ namespace Avalonia.X11
 
         }
 
-
         public int ScreenCount => _impl.Screens.Length;
 
         public IReadOnlyList<Screen> AllScreens =>
@@ -229,6 +250,7 @@ namespace Avalonia.X11
     class X11Screen
     {
         private const int FullHDWidth = 1920;
+        private const int FullHDHeight = 1080;
         public bool Primary { get; }
         public string Name { get; set; }
         public PixelRect Bounds { get; set; }
@@ -248,7 +270,7 @@ namespace Avalonia.X11
             }
             else if (pixelDensity == null)
             {
-                PixelDensity = GuessPixelDensity(bounds.Width, physicalSize.Value.Width);
+                PixelDensity = GuessPixelDensity(bounds, physicalSize.Value);
             }
             else
             {
@@ -257,7 +279,26 @@ namespace Avalonia.X11
             }
         }
 
-        public static double GuessPixelDensity(double pixelWidth, double mmWidth)
-            => pixelWidth <= FullHDWidth ? 1 : Math.Max(1, Math.Round(pixelWidth / mmWidth * 25.4 / 96));
+        public static double GuessPixelDensity(PixelRect pixel, Size physical)
+        {
+            var calculatedDensity = 1d;
+            if(physical.Width > 0)
+                calculatedDensity = pixel.Width <= FullHDWidth ? 1 : Math.Max(1, pixel.Width / physical.Width * 25.4 / 96);
+            else if(physical.Height > 0)
+                calculatedDensity = pixel.Height <= FullHDHeight ? 1 : Math.Max(1, pixel.Height / physical.Height * 25.4 / 96);
+            
+            if(calculatedDensity > 3)
+                return 1;
+            else
+            {
+                var sanePixelDensities = new double[] { 1, 1.25, 1.50, 1.75, 2 };
+                foreach(var saneDensity in sanePixelDensities)
+                {
+                    if(calculatedDensity <= saneDensity + 0.20)
+                        return saneDensity;
+                }
+                return sanePixelDensities.Last();
+            }
+        }
     }
 }
diff --git a/src/Avalonia.X11/XLib.cs b/src/Avalonia.X11/XLib.cs
index 85aa4862b7..92308cb7a1 100644
--- a/src/Avalonia.X11/XLib.cs
+++ b/src/Avalonia.X11/XLib.cs
@@ -500,6 +500,13 @@ namespace Avalonia.X11
         [DllImport(libX11Randr)]
         public static extern XRRMonitorInfo*
             XRRGetMonitors(IntPtr dpy, IntPtr window, bool get_active, out int nmonitors);
+
+        [DllImport(libX11Randr)]
+        public static extern IntPtr* XRRListOutputProperties(IntPtr dpy, long output, out int count);
+
+        [DllImport(libX11Randr)]
+        public static extern int XRRGetOutputProperty(IntPtr dpy, long output, IntPtr atom, long offset, long length, bool _delete, bool pending, IntPtr req_type, out int actual_type, out int actual_format, out int nitems, out long bytes_after, out IntPtr prop);
+            
         [DllImport(libX11Randr)]
         public static extern void XRRSelectInput(IntPtr dpy, IntPtr window, RandrEventMask mask);
 

From 8ae3a9f3580e65a6b00e119c758f5a10f83bb59a Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Tue, 15 Dec 2020 23:11:54 -0500
Subject: [PATCH 02/23] Fix DataGridColumn.DisplayIndex initial value handling

---
 samples/ControlCatalog/Pages/DataGridPage.xaml |  4 ++--
 src/Avalonia.Controls.DataGrid/DataGrid.cs     | 18 ++++++++++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/samples/ControlCatalog/Pages/DataGridPage.xaml b/samples/ControlCatalog/Pages/DataGridPage.xaml
index cacc2204bd..6817d0698e 100644
--- a/samples/ControlCatalog/Pages/DataGridPage.xaml
+++ b/samples/ControlCatalog/Pages/DataGridPage.xaml
@@ -38,8 +38,8 @@
           <DataGrid.Columns>
             <DataGridTextColumn Header="Country" Binding="{Binding Name}" Width="6*" />
             <DataGridTextColumn Header="Region" Binding="{Binding Region}" Width="4*" />
-            <DataGridTextColumn Header="Population" Binding="{Binding Population}" Width="3*" />
-            <DataGridTextColumn Header="Area" Binding="{Binding Area}" Width="3*" />
+            <DataGridTextColumn DisplayIndex="3" Header="Population" Binding="{Binding Population}" Width="3*" />
+            <DataGridTextColumn DisplayIndex="2" Header="Area" Binding="{Binding Area}" Width="3*" />
             <DataGridTextColumn Header="GDP" Binding="{Binding GDP}" Width="3*" />
           </DataGrid.Columns>
         </DataGrid>
diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 5bb2763566..e582153f41 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -2285,6 +2285,17 @@ namespace Avalonia.Controls
             }
         }
 
+        /// <summary>
+        /// Comparator class so we can sort list by the display index
+        /// </summary>
+        public class DisplayIndexComparer : IComparer<DataGridColumn>
+        {
+            int IComparer<DataGridColumn>.Compare(DataGridColumn x, DataGridColumn y)
+            {
+                return (x.DisplayIndexWithFiller < y.DisplayIndexWithFiller) ? -1 : 1;
+            }
+        }
+
         /// <summary>
         /// Builds the visual tree for the column header when a new template is applied.
         /// </summary>
@@ -2309,8 +2320,11 @@ namespace Avalonia.Controls
                     ColumnsInternal.FillerColumn.IsRepresented = false;
                 }
                 _columnHeadersPresenter.OwningGrid = this;
-                // Columns were added before before our Template was applied, add the ColumnHeaders now
-                foreach (DataGridColumn column in ColumnsItemsInternal)
+
+                // Columns were added before our Template was applied, add the ColumnHeaders now
+                List<DataGridColumn> sortedInternal = new List<DataGridColumn>(ColumnsItemsInternal);
+                sortedInternal.Sort(new DisplayIndexComparer());
+                foreach (DataGridColumn column in sortedInternal)
                 {
                     InsertDisplayedColumnHeader(column);
                 }

From c2b405b45c15cf102e3ae354a0ca1ef3bccf801c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Wies=C5=82aw=20=C5=A0olt=C3=A9s?=
 <wieslawsoltes@users.noreply.github.com>
Date: Wed, 16 Dec 2020 09:04:56 +0000
Subject: [PATCH 03/23] Set correct pointerover brush for expander control

---
 src/Avalonia.Themes.Fluent/Controls/Expander.xaml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Themes.Fluent/Controls/Expander.xaml b/src/Avalonia.Themes.Fluent/Controls/Expander.xaml
index 97ca62c493..ad0fd18ea5 100644
--- a/src/Avalonia.Themes.Fluent/Controls/Expander.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/Expander.xaml
@@ -108,7 +108,7 @@
     </Setter>
   </Style>
   <Style Selector="Expander /template/ ToggleButton#PART_toggle:pointerover /template/ Border">
-    <Setter Property="BorderBrush" Value="{DynamicResource SystemControlTransientBorderBrush}" />
+    <Setter Property="BorderBrush" Value="{DynamicResource SystemControlHighlightBaseMediumBrush}" />
   </Style>
   <Style Selector="Expander:down:expanded /template/ ToggleButton#PART_toggle /template/ Path">
     <Setter Property="RenderTransform">

From 43fcb52219b25818e32dea947171d79f6a06c625 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 20 Dec 2020 07:29:53 -0500
Subject: [PATCH 04/23] [Fluent] Prefer DynamicResource for resources used in
 controls

---
 src/Avalonia.Themes.Fluent/Controls/Button.xaml        |  3 +--
 .../Controls/CalendarDatePicker.xaml                   |  2 +-
 src/Avalonia.Themes.Fluent/Controls/DatePicker.xaml    |  4 ++--
 src/Avalonia.Themes.Fluent/Controls/FocusAdorner.xaml  |  6 +++---
 src/Avalonia.Themes.Fluent/Controls/ListBoxItem.xaml   |  2 +-
 src/Avalonia.Themes.Fluent/Controls/Menu.xaml          |  2 +-
 src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml      |  6 +++---
 src/Avalonia.Themes.Fluent/Controls/TabControl.xaml    |  2 +-
 src/Avalonia.Themes.Fluent/Controls/TabItem.xaml       | 10 +++++-----
 src/Avalonia.Themes.Fluent/Controls/TabStripItem.xaml  |  2 +-
 src/Avalonia.Themes.Fluent/Controls/TimePicker.xaml    |  4 ++--
 src/Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml  |  2 +-
 12 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/Controls/Button.xaml b/src/Avalonia.Themes.Fluent/Controls/Button.xaml
index 573b9f337f..597f5d00ec 100644
--- a/src/Avalonia.Themes.Fluent/Controls/Button.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/Button.xaml
@@ -16,8 +16,7 @@
     <Setter Property="Foreground" Value="{DynamicResource ButtonForeground}" />
     <Setter Property="BorderBrush" Value="{DynamicResource ButtonBorderBrush}" />
     <Setter Property="BorderThickness" Value="{DynamicResource ButtonBorderThemeThickness}" />
-    <Setter Property="Padding" Value="8,5,8,5" />
-    <Setter Property="Padding" Value="{StaticResource ButtonPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource ButtonPadding}" />
     <Setter Property="HorizontalAlignment" Value="Left" />
     <Setter Property="VerticalAlignment" Value="Center" />    
     <Setter Property="FontWeight" Value="Normal" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
index 75343ebb4a..a5d0c722ec 100644
--- a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
@@ -74,7 +74,7 @@
                                Grid.Row="1"
                                Grid.ColumnSpan="4"
                                Grid.RowSpan="3"
-                               FontSize="{StaticResource CalendarDatePickerCurrentDayFontSize}"
+                               FontSize="{DynamicResource CalendarDatePickerCurrentDayFontSize}"
                                Text="{Binding Source={x:Static sys:DateTime.Today}, Path=Day}"/>
 
                     <Ellipse HorizontalAlignment="Center" VerticalAlignment="Center" Fill="{DynamicResource SystemControlBackgroundChromeBlackHighBrush}" StrokeThickness="0" Grid.ColumnSpan="4" Width="3" Height="3"/>
diff --git a/src/Avalonia.Themes.Fluent/Controls/DatePicker.xaml b/src/Avalonia.Themes.Fluent/Controls/DatePicker.xaml
index b6e36861e0..032fdd9ae4 100644
--- a/src/Avalonia.Themes.Fluent/Controls/DatePicker.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/DatePicker.xaml
@@ -141,8 +141,8 @@
                     BorderBrush="{TemplateBinding BorderBrush}"
                     BorderThickness="{TemplateBinding BorderThickness}"
                     IsEnabled="{TemplateBinding IsEnabled}"
-                    MinWidth="{StaticResource DatePickerThemeMinWidth}"
-                    MaxWidth="{StaticResource DatePickerThemeMaxWidth}"
+                    MinWidth="{DynamicResource DatePickerThemeMinWidth}"
+                    MaxWidth="{DynamicResource DatePickerThemeMaxWidth}"
                     HorizontalAlignment="Stretch"
                     VerticalAlignment="Stretch"
                     HorizontalContentAlignment="Stretch"
diff --git a/src/Avalonia.Themes.Fluent/Controls/FocusAdorner.xaml b/src/Avalonia.Themes.Fluent/Controls/FocusAdorner.xaml
index f20dc2e650..e6577497da 100644
--- a/src/Avalonia.Themes.Fluent/Controls/FocusAdorner.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/FocusAdorner.xaml
@@ -10,10 +10,10 @@
   <Style Selector=":is(Control)">
     <Setter Property="FocusAdorner">
       <FocusAdornerTemplate>
-        <Border BorderThickness="{StaticResource SystemControlFocusVisualPrimaryThickness}"
+        <Border BorderThickness="{DynamicResource SystemControlFocusVisualPrimaryThickness}"
                 BorderBrush="{DynamicResource SystemControlFocusVisualPrimaryBrush}"
-                Margin="{StaticResource SystemControlFocusVisualMargin}">
-          <Border BorderThickness="{StaticResource SystemControlFocusVisualSecondaryThickness}"
+                Margin="{DynamicResource SystemControlFocusVisualMargin}">
+          <Border BorderThickness="{DynamicResource SystemControlFocusVisualSecondaryThickness}"
                   BorderBrush="{DynamicResource SystemControlFocusVisualSecondaryBrush}" />
         </Border>
       </FocusAdornerTemplate>
diff --git a/src/Avalonia.Themes.Fluent/Controls/ListBoxItem.xaml b/src/Avalonia.Themes.Fluent/Controls/ListBoxItem.xaml
index 7715ddf1f1..627ffa2b19 100644
--- a/src/Avalonia.Themes.Fluent/Controls/ListBoxItem.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/ListBoxItem.xaml
@@ -17,7 +17,7 @@
   </Styles.Resources>
   <Style Selector="ListBoxItem">
     <Setter Property="Background" Value="Transparent" />
-    <Setter Property="Padding" Value="{StaticResource ListBoxItemPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource ListBoxItemPadding}" />
     <Setter Property="HorizontalContentAlignment" Value="Left" />
     <Setter Property="Template">
       <ControlTemplate>
diff --git a/src/Avalonia.Themes.Fluent/Controls/Menu.xaml b/src/Avalonia.Themes.Fluent/Controls/Menu.xaml
index e62b76d293..34e6f173d5 100644
--- a/src/Avalonia.Themes.Fluent/Controls/Menu.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/Menu.xaml
@@ -16,7 +16,7 @@
   </Style.Resources>
 
   <Setter Property="Background" Value="Transparent" />
-  <Setter Property="Height" Value="{StaticResource MenuBarHeight}" />
+  <Setter Property="Height" Value="{DynamicResource MenuBarHeight}" />
   <Setter Property="Template">
     <ControlTemplate>
       <Border Background="{TemplateBinding Background}"
diff --git a/src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml b/src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml
index fff7baf3bd..39683b837c 100644
--- a/src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/MenuItem.xaml
@@ -112,7 +112,7 @@
           <Popup Name="PART_Popup"
                  WindowManagerAddShadowHint="False"
                  PlacementMode="Right"
-                 HorizontalOffset="{StaticResource MenuFlyoutSubItemPopupHorizontalOffset}"
+                 HorizontalOffset="{DynamicResource MenuFlyoutSubItemPopupHorizontalOffset}"
                  IsLightDismissEnabled="True"
                  IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
             <Border Background="{DynamicResource MenuFlyoutPresenterBackground}"
@@ -189,12 +189,12 @@
 
   <Style Selector="MenuItem">
     <!--  Narrow padding should be used for mouse input, when non-narrow one should be used for touch input in future.  -->
-    <Setter Property="Padding" Value="{StaticResource MenuFlyoutItemThemePaddingNarrow}" />
+    <Setter Property="Padding" Value="{DynamicResource MenuFlyoutItemThemePaddingNarrow}" />
   </Style>
 
   <Style Selector="Menu > MenuItem">
     <!--  Custom padding for Menu > MenuItem  -->
-    <Setter Property="Padding" Value="{StaticResource MenuBarItemPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource MenuBarItemPadding}" />
   </Style>
 
   <Style Selector="MenuItem /template/ ContentPresenter#PART_IconPresenter">
diff --git a/src/Avalonia.Themes.Fluent/Controls/TabControl.xaml b/src/Avalonia.Themes.Fluent/Controls/TabControl.xaml
index c38ecb0452..120b2986c3 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TabControl.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TabControl.xaml
@@ -60,6 +60,6 @@
     <Setter Property="Orientation" Value="Vertical" />
   </Style>
   <Style Selector="TabControl[TabStripPlacement=Top] /template/ ItemsPresenter#PART_ItemsPresenter">
-    <Setter Property="Margin" Value="{StaticResource TabControlTopPlacementItemMargin}" />
+    <Setter Property="Margin" Value="{DynamicResource TabControlTopPlacementItemMargin}" />
   </Style>
 </Styles>
diff --git a/src/Avalonia.Themes.Fluent/Controls/TabItem.xaml b/src/Avalonia.Themes.Fluent/Controls/TabItem.xaml
index 1c9574f169..508473796c 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TabItem.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TabItem.xaml
@@ -97,8 +97,8 @@
 
   <!-- TabStripPlacement States Group -->
   <Style Selector="TabItem[TabStripPlacement=Left] /template/ Border#PART_SelectedPipe">
-    <Setter Property="Width" Value="{StaticResource TabItemPipeThickness}" />
-    <Setter Property="Height" Value="{StaticResource TabItemVerticalPipeHeight}" />
+    <Setter Property="Width" Value="{DynamicResource TabItemPipeThickness}" />
+    <Setter Property="Height" Value="{DynamicResource TabItemVerticalPipeHeight}" />
     <Setter Property="Margin" Value="0,0,2,0" />
     <Setter Property="HorizontalAlignment" Value="Left" />
     <Setter Property="VerticalAlignment" Value="Center" />
@@ -108,15 +108,15 @@
   </Style>
 
   <Style Selector="TabItem[TabStripPlacement=Top] /template/ Border#PART_SelectedPipe, TabItem[TabStripPlacement=Bottom] /template/ Border#PART_SelectedPipe">
-    <Setter Property="Height" Value="{StaticResource TabItemPipeThickness}" />
+    <Setter Property="Height" Value="{DynamicResource TabItemPipeThickness}" />
     <Setter Property="Margin" Value="0,0,0,2" />
     <Setter Property="HorizontalAlignment" Value="Stretch" />
     <Setter Property="VerticalAlignment" Value="Bottom" />
   </Style>
 
   <Style Selector="TabItem[TabStripPlacement=Right] /template/ Border#PART_SelectedPipe">
-    <Setter Property="Width" Value="{StaticResource TabItemPipeThickness}" />
-    <Setter Property="Height" Value="{StaticResource TabItemVerticalPipeHeight}" />
+    <Setter Property="Width" Value="{DynamicResource TabItemPipeThickness}" />
+    <Setter Property="Height" Value="{DynamicResource TabItemVerticalPipeHeight}" />
     <Setter Property="Margin" Value="2,0,0,0" />
     <Setter Property="HorizontalAlignment" Value="Right" />
     <Setter Property="VerticalAlignment" Value="Center" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/TabStripItem.xaml b/src/Avalonia.Themes.Fluent/Controls/TabStripItem.xaml
index 78ef102705..69940eff25 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TabStripItem.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TabStripItem.xaml
@@ -57,7 +57,7 @@
     <Setter Property="IsVisible" Value="False" />
   </Style>
   <Style Selector="TabStripItem /template/ Border#PART_SelectedPipe, TabItem[TabStripPlacement=Bottom] /template/ Border#PART_SelectedPipe">
-    <Setter Property="Height" Value="{StaticResource TabStripItemPipeThickness}" />
+    <Setter Property="Height" Value="{DynamicResource TabStripItemPipeThickness}" />
     <Setter Property="Margin" Value="0,0,0,2" />
     <Setter Property="HorizontalAlignment" Value="Stretch" />
     <Setter Property="VerticalAlignment" Value="Bottom" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/TimePicker.xaml b/src/Avalonia.Themes.Fluent/Controls/TimePicker.xaml
index 91969d8733..1c52c6272c 100644
--- a/src/Avalonia.Themes.Fluent/Controls/TimePicker.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/TimePicker.xaml
@@ -60,8 +60,8 @@
                     BorderBrush="{TemplateBinding BorderBrush}"
                     BorderThickness="{TemplateBinding BorderThickness}"
                     IsEnabled="{TemplateBinding IsEnabled}"
-                    MinWidth="{StaticResource TimePickerThemeMinWidth}"
-                    MaxWidth="{StaticResource TimePickerThemeMaxWidth}"
+                    MinWidth="{DynamicResource TimePickerThemeMinWidth}"
+                    MaxWidth="{DynamicResource TimePickerThemeMaxWidth}"
                     HorizontalAlignment="Stretch"
                     HorizontalContentAlignment="Stretch"
                     VerticalAlignment="Top"
diff --git a/src/Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml b/src/Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml
index 45537e41ad..ef54769f22 100644
--- a/src/Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/ToggleSwitch.xaml
@@ -56,7 +56,7 @@
             VerticalAlignment="Top"/>
 
           <Grid Grid.Row="1"
-            MinWidth="{StaticResource ToggleSwitchThemeMinWidth}"
+            MinWidth="{DynamicResource ToggleSwitchThemeMinWidth}"
             HorizontalAlignment="Left"
             VerticalAlignment="Top">
 

From 4ce630e71a4d19f4e28c1cea35c95d47330474ef Mon Sep 17 00:00:00 2001
From: Robin Dostal <robin.dostal@medix.at>
Date: Sun, 20 Dec 2020 23:10:41 +0100
Subject: [PATCH 05/23] Changing XRRMonitorInfo.Outputs from IntPtr to IntPtr*

Change XRRMonitorInfo.Outputs from IntPtr to IntPtr* and iterate over
all Outputs to detect the smallest pixeldensity.
---
 src/Avalonia.X11/X11Screens.cs | 43 +++++++++++++++++++++++-----------
 src/Avalonia.X11/X11Structs.cs |  4 ++--
 src/Avalonia.X11/XLib.cs       |  4 ++--
 3 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/src/Avalonia.X11/X11Screens.cs b/src/Avalonia.X11/X11Screens.cs
index df1b2b7312..b51497fb13 100644
--- a/src/Avalonia.X11/X11Screens.cs
+++ b/src/Avalonia.X11/X11Screens.cs
@@ -66,7 +66,8 @@ namespace Avalonia.X11
             private X11Screen[] _cache;
             private X11Info _x11;
             private IntPtr _window;
-
+            const int EDIDStructureLength = 32; // Length of a EDID-Block-Length(128 bytes), XRRGetOutputProperty multiplies offset and length by 4
+            
             public Randr15ScreensImpl(AvaloniaX11Platform platform, X11ScreensUserSettings settings)
             {
                 _settings = settings;
@@ -86,8 +87,7 @@ namespace Avalonia.X11
             {
                 if(rrOutput == IntPtr.Zero)
                     return null;
-                var output = Marshal.ReadInt64(rrOutput);
-                var properties = XRRListOutputProperties(_x11.Display,output, out int propertyCount);
+                var properties = XRRListOutputProperties(_x11.Display,rrOutput, out int propertyCount);
                 var hasEDID = false;
                 for(var pc = 0; pc < propertyCount; pc++)
                 {
@@ -96,20 +96,20 @@ namespace Avalonia.X11
                 }
                 if(!hasEDID)
                     return null;
-                XRRGetOutputProperty(_x11.Display, output, _x11.Atoms.RR_PROPERTY_RANDR_EDID, 0, 128, false, false, _x11.Atoms.AnyPropertyType, out int actualType, out int actualFormat, out int nItems, out _, out IntPtr prop);
-                if(actualType != 19) // XA_INTEGER
+                XRRGetOutputProperty(_x11.Display, rrOutput, _x11.Atoms.RR_PROPERTY_RANDR_EDID, 0, EDIDStructureLength, false, false, _x11.Atoms.AnyPropertyType, out IntPtr actualType, out int actualFormat, out int bytesAfter, out _, out IntPtr prop);
+                if(actualType != _x11.Atoms.XA_INTEGER)
                     return null;
-                if(actualFormat != 8)
+                if(actualFormat != 8) // Expecting an byte array
                     return null;
 
-                var edid = new byte[nItems];
-                Marshal.Copy(prop,edid,0,nItems);
+                var edid = new byte[bytesAfter];
+                Marshal.Copy(prop,edid,0,bytesAfter);
                 XFree(prop);
                 XFree(new IntPtr(properties));
                 if(edid.Length < 22)
                     return null;
-                var width = edid[21];
-                var height = edid[22];
+                var width = edid[21]; // 0x15 1 Max. Horizontal Image Size cm. 
+                var height = edid[22]; // 0x16 1 Max. Vertical Image Size cm. 
                 if(width == 0 && height == 0)
                     return null;
                 return new Size(width * 10, height * 10);
@@ -131,10 +131,25 @@ namespace Avalonia.X11
                         var name = Marshal.PtrToStringAnsi(namePtr);
                         XFree(namePtr);
                         var bounds = new PixelRect(mon.X, mon.Y, mon.Width, mon.Height);
-                        var density = 1d;
-                        var pSize = GetPhysicalMonitorSizeFromEDID(mon.Outputs);
-                        if (_settings.NamedScaleFactors?.TryGetValue(name, out  density) != true && pSize != null)
-                            density = X11Screen.GuessPixelDensity(bounds, pSize.Value);
+                        Size? pSize = null;
+                        double density = 0;
+                        if (_settings.NamedScaleFactors?.TryGetValue(name, out density) != true)
+                        {
+                            for(int o = 0; o < mon.NOutput; o++)
+                            {
+                                var outputSize = GetPhysicalMonitorSizeFromEDID(mon.Outputs[o]);
+                                var outputDensity = 1d;
+                                if(outputSize != null)
+                                    outputDensity = X11Screen.GuessPixelDensity(bounds, outputSize.Value);
+                                if(density == 0 || density > outputDensity)
+                                {
+                                    density = outputDensity;
+                                    pSize = outputSize;
+                                }
+                            }
+                        }
+                        if(density == 0)
+                            density = 1;
                         density *= _settings.GlobalScaleFactor;
                         screens[c] = new X11Screen(bounds, mon.Primary != 0, name, pSize, density);
                     }
diff --git a/src/Avalonia.X11/X11Structs.cs b/src/Avalonia.X11/X11Structs.cs
index 0ae5c16aef..ae4954a2d5 100644
--- a/src/Avalonia.X11/X11Structs.cs
+++ b/src/Avalonia.X11/X11Structs.cs
@@ -1870,7 +1870,7 @@ namespace Avalonia.X11 {
 		public const string XNFontSet = "fontSet";
 	}
 	
-    struct XRRMonitorInfo {
+    unsafe struct XRRMonitorInfo {
         public IntPtr Name;
         public int Primary;
         public int Automatic;
@@ -1881,6 +1881,6 @@ namespace Avalonia.X11 {
         public int Height;
         public int MWidth;
         public int MHeight;
-        public IntPtr Outputs;
+        public IntPtr* Outputs;
     } 
 }
diff --git a/src/Avalonia.X11/XLib.cs b/src/Avalonia.X11/XLib.cs
index 92308cb7a1..bec94e63c9 100644
--- a/src/Avalonia.X11/XLib.cs
+++ b/src/Avalonia.X11/XLib.cs
@@ -502,10 +502,10 @@ namespace Avalonia.X11
             XRRGetMonitors(IntPtr dpy, IntPtr window, bool get_active, out int nmonitors);
 
         [DllImport(libX11Randr)]
-        public static extern IntPtr* XRRListOutputProperties(IntPtr dpy, long output, out int count);
+        public static extern IntPtr* XRRListOutputProperties(IntPtr dpy, IntPtr output, out int count);
 
         [DllImport(libX11Randr)]
-        public static extern int XRRGetOutputProperty(IntPtr dpy, long output, IntPtr atom, long offset, long length, bool _delete, bool pending, IntPtr req_type, out int actual_type, out int actual_format, out int nitems, out long bytes_after, out IntPtr prop);
+        public static extern int XRRGetOutputProperty(IntPtr dpy, IntPtr output, IntPtr atom, int offset, int length, bool _delete, bool pending, IntPtr req_type, out IntPtr actual_type, out int actual_format, out int nitems, out long bytes_after, out IntPtr prop);
             
         [DllImport(libX11Randr)]
         public static extern void XRRSelectInput(IntPtr dpy, IntPtr window, RandrEventMask mask);

From 5109b00644ea834ab65bc6f9681e6a7717458634 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 20 Dec 2020 18:04:01 -0500
Subject: [PATCH 06/23] Reuse PropertyType in the ShouldNotSet method

---
 src/Avalonia.Base/Data/Core/SettableNode.cs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Base/Data/Core/SettableNode.cs b/src/Avalonia.Base/Data/Core/SettableNode.cs
index d0a918dc88..363d3da0ef 100644
--- a/src/Avalonia.Base/Data/Core/SettableNode.cs
+++ b/src/Avalonia.Base/Data/Core/SettableNode.cs
@@ -15,7 +15,8 @@ namespace Avalonia.Data.Core
 
         private bool ShouldNotSet(object value)
         {
-            if (PropertyType == null)
+            var propertyType = PropertyType;
+            if (propertyType == null)
             {
                 return false;
             }
@@ -37,7 +38,7 @@ namespace Avalonia.Data.Core
                 return false;
             }
 
-            if (PropertyType.IsValueType)
+            if (propertyType.IsValueType)
             {
                 return lastValue.Equals(value);
             }

From b240fc7d0c75bbfc2e060c78b67e4af4278e638f Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 20 Dec 2020 18:05:59 -0500
Subject: [PATCH 07/23] Add failing and working tests for null DataContext

---
 .../AvaloniaObjectTests_Binding.cs            | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
index 7fc0d52be6..7c4c5c96a5 100644
--- a/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
+++ b/tests/Avalonia.Base.UnitTests/AvaloniaObjectTests_Binding.cs
@@ -4,6 +4,8 @@ using System.Reactive.Linq;
 using System.Reactive.Subjects;
 using System.Threading;
 using System.Threading.Tasks;
+
+using Avalonia.Controls;
 using Avalonia.Data;
 using Avalonia.Logging;
 using Avalonia.Platform;
@@ -797,6 +799,24 @@ namespace Avalonia.Base.UnitTests
             Assert.False(source.SetterCalled);
         }
 
+        [Fact]
+        public void TwoWay_Binding_Should_Not_Fail_With_Null_DataContext()
+        {
+            var target = new TextBlock();
+            target.DataContext = null;
+
+            target.Bind(TextBlock.TextProperty, new Binding("Missing", BindingMode.TwoWay));
+        }
+
+        [Fact]
+        public void TwoWay_Binding_Should_Not_Fail_With_Null_DataContext_Indexer()
+        {
+            var target = new TextBlock();
+            target.DataContext = null;
+
+            target.Bind(TextBlock.TextProperty, new Binding("[0]", BindingMode.TwoWay));
+        }
+
         [Fact]
         public void Disposing_Completed_Binding_Does_Not_Throw()
         {

From d020d9872cbd385b8bf124b224f611bf58d15a43 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 20 Dec 2020 18:07:06 -0500
Subject: [PATCH 08/23] Fix failing test when DataContext is null

---
 .../Markup/Parsers/Nodes/StringIndexerNode.cs                | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/Markup/Avalonia.Markup/Markup/Parsers/Nodes/StringIndexerNode.cs b/src/Markup/Avalonia.Markup/Markup/Parsers/Nodes/StringIndexerNode.cs
index 76fbc9a982..f3abd6a5c5 100644
--- a/src/Markup/Avalonia.Markup/Markup/Parsers/Nodes/StringIndexerNode.cs
+++ b/src/Markup/Avalonia.Markup/Markup/Parsers/Nodes/StringIndexerNode.cs
@@ -129,7 +129,10 @@ namespace Avalonia.Markup.Parsers.Nodes
         {
             get
             {
-                Target.TryGetTarget(out object target);
+                if (!Target.TryGetTarget(out object target))
+                {
+                    return null;
+                }
 
                 return GetIndexer(target.GetType().GetTypeInfo())?.PropertyType;
             }

From a01fb157e400befa2e477549867d22a0cabec3e3 Mon Sep 17 00:00:00 2001
From: Andrey Kunchev <donandren@gmail.com>
Date: Mon, 21 Dec 2020 12:53:31 +0200
Subject: [PATCH 09/23] add some tests for contextmenu open without params

---
 .../ContextMenuTests.cs                       | 49 +++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs b/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
index 39a3250686..f3a1316c7d 100644
--- a/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/ContextMenuTests.cs
@@ -44,6 +44,55 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
+        [Fact]
+        public void Open_Should_Use_Default_Control()
+        {
+            using (Application())
+            {
+                var sut = new ContextMenu();
+                var target = new Panel
+                {
+                    ContextMenu = sut
+                };
+
+                var window = new Window { Content = target };
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+
+                bool opened = false;
+
+                sut.MenuOpened += (sender, args) =>
+                {
+                    opened = true;
+                };
+
+                sut.Open();
+
+                Assert.True(opened);
+            }
+        }
+
+        [Fact]
+        public void Open_Should_Raise_Exception_If_AlreadyDetached()
+        {
+            using (Application())
+            {
+                var sut = new ContextMenu();
+                var target = new Panel
+                {
+                    ContextMenu = sut
+                };
+
+                var window = new Window { Content = target };
+                window.ApplyTemplate();
+                window.Presenter.ApplyTemplate();
+
+                target.ContextMenu = null;
+
+               Assert.ThrowsAny<Exception>(()=> sut.Open());
+            }
+        }
+
         [Fact]
         public void Closing_Raises_Single_Closed_Event()
         {

From a045e963ac2a6def331ace62b977b52bc89636b6 Mon Sep 17 00:00:00 2001
From: Andrey Kunchev <donandren@gmail.com>
Date: Mon, 21 Dec 2020 12:54:23 +0200
Subject: [PATCH 10/23] ContextMenu.Open should call Open(null) so it doesn't
 break working scenarios

---
 src/Avalonia.Controls/ContextMenu.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls/ContextMenu.cs b/src/Avalonia.Controls/ContextMenu.cs
index 5e17182f3e..fb8080f0d4 100644
--- a/src/Avalonia.Controls/ContextMenu.cs
+++ b/src/Avalonia.Controls/ContextMenu.cs
@@ -246,7 +246,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// Opens the menu.
         /// </summary>
-        public override void Open() => throw new NotSupportedException();
+        public override void Open() => Open(null);
 
         /// <summary>
         /// Opens a context menu on the specified control.

From 94b8a3b1406a0b709423f00a7cda5d17ca69609d Mon Sep 17 00:00:00 2001
From: Giuseppe Lippolis <workgroupengineering@outlook.com>
Date: Mon, 21 Dec 2020 13:05:25 +0100
Subject: [PATCH 11/23] Hide package icon on projects

---
 build/SharedVersion.props | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build/SharedVersion.props b/build/SharedVersion.props
index 43ec995ed9..9a268a21e7 100644
--- a/build/SharedVersion.props
+++ b/build/SharedVersion.props
@@ -21,6 +21,6 @@
   </PropertyGroup>
 
   <ItemGroup Label="PackageIcon">
-    <None Include="$(MSBuildThisFileDirectory)/Assets/Icon.png" Pack="true" PackagePath=""/>
+    <None Include="$(MSBuildThisFileDirectory)/Assets/Icon.png" Pack="true" Visible="false" PackagePath=""/>
   </ItemGroup>
 </Project>

From eeb2745db577d52d40eaaec64a179d99ea445f68 Mon Sep 17 00:00:00 2001
From: Mike Ward <mike@mike-ward.net>
Date: Mon, 21 Dec 2020 10:27:28 -0600
Subject: [PATCH 12/23] Fix #5151 same as Microsoft

---
 src/Avalonia.Layout/ElementManager.cs | 87 +++++++++++++--------------
 1 file changed, 43 insertions(+), 44 deletions(-)

diff --git a/src/Avalonia.Layout/ElementManager.cs b/src/Avalonia.Layout/ElementManager.cs
index 70805ba31c..bf5a45966b 100644
--- a/src/Avalonia.Layout/ElementManager.cs
+++ b/src/Avalonia.Layout/ElementManager.cs
@@ -129,7 +129,7 @@ namespace Avalonia.Layout
         {
             for (int i = 0; i < count; i++)
             {
-                // Clear from the edges so that ItemsRepeater can optimize on maintaining 
+                // Clear from the edges so that ItemsRepeater can optimize on maintaining
                 // realized indices without walking through all the children every time.
                 int index = realizedIndex == 0 ? realizedIndex + i : (realizedIndex + count - 1) - i;
                 var elementRef = _realizedElements[index];
@@ -212,7 +212,7 @@ namespace Avalonia.Layout
         public ILayoutable GetRealizedElement(int dataIndex)
         {
             return IsVirtualizingContext ?
-                GetAt(GetRealizedRangeIndexFromDataIndex(dataIndex)) : 
+                GetAt(GetRealizedRangeIndexFromDataIndex(dataIndex)) :
                 _context.GetOrCreateElementAt(
                     dataIndex,
                     ElementRealizationOptions.ForceCreate | ElementRealizationOptions.SuppressAutoRecycle);
@@ -252,7 +252,6 @@ namespace Avalonia.Layout
                     (orientation == ScrollOrientation.Vertical ? ScrollOrientation.Horizontal : ScrollOrientation.Vertical) :
                     orientation;
 
-
                 var windowStart = effectiveOrientation == ScrollOrientation.Vertical ? window.Y : window.X;
                 var windowEnd = effectiveOrientation == ScrollOrientation.Vertical ? window.Y + window.Height : window.X + window.Width;
                 var firstElementStart = effectiveOrientation == ScrollOrientation.Vertical ? firstElementBounds.Y : firstElementBounds.X;
@@ -273,53 +272,53 @@ namespace Avalonia.Layout
                 switch (args.Action)
                 {
                     case NotifyCollectionChangedAction.Add:
-                    {
-                        OnItemsAdded(args.NewStartingIndex, args.NewItems.Count);
-                    }
-                    break;
+                        {
+                            OnItemsAdded(args.NewStartingIndex, args.NewItems.Count);
+                        }
+                        break;
 
                     case NotifyCollectionChangedAction.Replace:
-                    {
-                        int oldSize = args.OldItems.Count;
-                        int newSize = args.NewItems.Count;
-                        int oldStartIndex = args.OldStartingIndex;
-                        int newStartIndex = args.NewStartingIndex;
-
-                        if (oldSize == newSize &&
-                            oldStartIndex == newStartIndex &&
-                            IsDataIndexRealized(oldStartIndex) &&
-                            IsDataIndexRealized(oldStartIndex + oldSize -1))
                         {
-                            // Straight up replace of n items within the realization window.
-                            // Removing and adding might causes us to lose the anchor causing us
-                            // to throw away all containers and start from scratch.
-                            // Instead, we can just clear those items and set the element to
-                            // null (sentinel) and let the next measure get new containers for them.
-                            var startRealizedIndex = GetRealizedRangeIndexFromDataIndex(oldStartIndex);
-                            for (int realizedIndex = startRealizedIndex; realizedIndex < startRealizedIndex + oldSize; realizedIndex++)
+                            int oldSize = args.OldItems.Count;
+                            int newSize = args.NewItems.Count;
+                            int oldStartIndex = args.OldStartingIndex;
+                            int newStartIndex = args.NewStartingIndex;
+
+                            if (oldSize == newSize &&
+                                oldStartIndex == newStartIndex &&
+                                IsDataIndexRealized(oldStartIndex) &&
+                                IsDataIndexRealized(oldStartIndex + oldSize - 1))
                             {
-                                var elementRef = _realizedElements[realizedIndex];
-
-                                if (elementRef != null)
+                                // Straight up replace of n items within the realization window.
+                                // Removing and adding might causes us to lose the anchor causing us
+                                // to throw away all containers and start from scratch.
+                                // Instead, we can just clear those items and set the element to
+                                // null (sentinel) and let the next measure get new containers for them.
+                                var startRealizedIndex = GetRealizedRangeIndexFromDataIndex(oldStartIndex);
+                                for (int realizedIndex = startRealizedIndex; realizedIndex < startRealizedIndex + oldSize; realizedIndex++)
                                 {
-                                    _context.RecycleElement(elementRef);
-                                    _realizedElements[realizedIndex] = null;
+                                    var elementRef = _realizedElements[realizedIndex];
+
+                                    if (elementRef != null)
+                                    {
+                                        _context.RecycleElement(elementRef);
+                                        _realizedElements[realizedIndex] = null;
+                                    }
                                 }
                             }
+                            else
+                            {
+                                OnItemsRemoved(oldStartIndex, oldSize);
+                                OnItemsAdded(newStartIndex, newSize);
+                            }
                         }
-                        else
-                        {
-                            OnItemsRemoved(oldStartIndex, oldSize);
-                            OnItemsAdded(newStartIndex, newSize);
-                        }
-                    }
-                    break;
+                        break;
 
                     case NotifyCollectionChangedAction.Remove:
-                    {
-                        OnItemsRemoved(args.OldStartingIndex, args.OldItems.Count);
-                    }
-                    break;
+                        {
+                            OnItemsRemoved(args.OldStartingIndex, args.OldItems.Count);
+                        }
+                        break;
 
                     case NotifyCollectionChangedAction.Reset:
                         ClearRealizedRange();
@@ -376,7 +375,7 @@ namespace Avalonia.Layout
             int backCutoffIndex = realizedRangeSize;
 
             for (int i = 0;
-                i<realizedRangeSize &&
+                i < realizedRangeSize &&
                 !Intersects(window, _realizedElementLayoutBounds[i], orientation);
                 ++i)
             {
@@ -391,7 +390,7 @@ namespace Avalonia.Layout
                 --backCutoffIndex;
             }
 
-            if (backCutoffIndex<realizedRangeSize - 1)
+            if (backCutoffIndex < realizedRangeSize - 1)
             {
                 ClearRealizedRange(backCutoffIndex + 1, realizedRangeSize - backCutoffIndex - 1);
             }
@@ -419,14 +418,14 @@ namespace Avalonia.Layout
             // to insert items.
             int lastRealizedDataIndex = _firstRealizedDataIndex + GetRealizedElementCount() - 1;
             int newStartingIndex = index;
-            if (newStartingIndex > _firstRealizedDataIndex &&
+            if (newStartingIndex >= _firstRealizedDataIndex &&
                 newStartingIndex <= lastRealizedDataIndex)
             {
                 // Inserted within the realized range
                 int insertRangeStartIndex = newStartingIndex - _firstRealizedDataIndex;
                 for (int i = 0; i < count; i++)
                 {
-                    // Insert null (sentinel) here instead of an element, that way we dont 
+                    // Insert null (sentinel) here instead of an element, that way we dont
                     // end up creating a lot of elements only to be thrown out in the next layout.
                     int insertRangeIndex = insertRangeStartIndex + i;
                     int dataIndex = newStartingIndex + i;

From 2384b07ab88b7edb927a6969d1298af66294bf13 Mon Sep 17 00:00:00 2001
From: Anton Ryzhov <anton.ryzhov@vertoanalytics.com>
Date: Thu, 24 Dec 2020 22:00:52 +0200
Subject: [PATCH 13/23] DataGrid: Extracting error data from
 DataValidationException #5222

---
 src/Avalonia.Controls.DataGrid/DataGrid.cs    | 107 +++++++++---------
 .../Utils/ValidationUtil.cs                   |  25 ++--
 2 files changed, 69 insertions(+), 63 deletions(-)

diff --git a/src/Avalonia.Controls.DataGrid/DataGrid.cs b/src/Avalonia.Controls.DataGrid/DataGrid.cs
index 5bb2763566..6687c59aa4 100644
--- a/src/Avalonia.Controls.DataGrid/DataGrid.cs
+++ b/src/Avalonia.Controls.DataGrid/DataGrid.cs
@@ -1,6 +1,6 @@
 // This source is subject to the Microsoft Public License (Ms-PL).
 // Please see http://go.microsoft.com/fwlink/?LinkID=131993 for details.
-// All other rights reserved. 
+// All other rights reserved.
 
 using Avalonia.Collections;
 using Avalonia.Controls.Primitives;
@@ -92,7 +92,7 @@ namespace Avalonia.Controls
         private ContentControl _topRightCornerHeader;
         private Control _frozenColumnScrollBarSpacer;
 
-        // the sum of the widths in pixels of the scrolling columns preceding 
+        // the sum of the widths in pixels of the scrolling columns preceding
         // the first displayed scrolling column
         private double _horizontalOffset;
 
@@ -143,7 +143,7 @@ namespace Avalonia.Controls
         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 
+        // 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
         // does not know their actual height. The heights used for the approximation are the ones
         // set as the rows were scrolled off.
@@ -162,7 +162,7 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<DataGrid, bool>(nameof(CanUserReorderColumns));
 
         /// <summary>
-        /// Gets or sets a value that indicates whether the user can change 
+        /// Gets or sets a value that indicates whether the user can change
         /// the column display order by dragging column headers with the mouse.
         /// </summary>
         public bool CanUserReorderColumns
@@ -247,8 +247,8 @@ namespace Avalonia.Controls
         /// Gets or sets the <see cref="T:System.Windows.Media.Brush" /> that is used to paint the background of odd-numbered rows.
         /// </summary>
         /// <returns>
-        /// The brush that is used to paint the background of odd-numbered rows. The default is a 
-        /// <see cref="T:System.Windows.Media.SolidColorBrush" /> with a 
+        /// The brush that is used to paint the background of odd-numbered rows. The default is a
+        /// <see cref="T:System.Windows.Media.SolidColorBrush" /> with a
         /// <see cref="P:System.Windows.Media.SolidColorBrush.Color" /> value of white (ARGB value #00FFFFFF).
         /// </returns>
         public IBrush AlternatingRowBackground
@@ -379,8 +379,8 @@ namespace Avalonia.Controls
         public bool IsValid
         {
             get { return _isValid; }
-            internal set 
-            { 
+            internal set
+            {
                 SetAndRaise(IsValidProperty, ref _isValid, value);
                 PseudoClasses.Set(":invalid", !value);
             }
@@ -398,7 +398,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Gets or sets the maximum width of columns in the <see cref="T:Avalonia.Controls.DataGrid" /> . 
+        /// Gets or sets the maximum width of columns in the <see cref="T:Avalonia.Controls.DataGrid" /> .
         /// </summary>
         public double MaxColumnWidth
         {
@@ -418,7 +418,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Gets or sets the minimum width of columns in the <see cref="T:Avalonia.Controls.DataGrid" />. 
+        /// Gets or sets the minimum width of columns in the <see cref="T:Avalonia.Controls.DataGrid" />.
         /// </summary>
         public double MinColumnWidth
         {
@@ -496,7 +496,7 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<DataGrid, IBrush>(nameof(VerticalGridLinesBrush));
 
         /// <summary>
-        /// Gets or sets the <see cref="T:System.Windows.Media.Brush" /> that is used to paint grid lines separating columns. 
+        /// Gets or sets the <see cref="T:System.Windows.Media.Brush" /> that is used to paint grid lines separating columns.
         /// </summary>
         public IBrush VerticalGridLinesBrush
         {
@@ -542,7 +542,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <returns>
         /// The index of the current selection, or -1 if the selection is empty.
-        /// </returns> 
+        /// </returns>
         public int SelectedIndex
         {
             get { return _selectedIndex; }
@@ -582,7 +582,7 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<DataGrid, bool>(nameof(AutoGenerateColumns));
 
         /// <summary>
-        /// Gets or sets a value that indicates whether columns are created 
+        /// Gets or sets a value that indicates whether columns are created
         /// automatically when the <see cref="P:Avalonia.Controls.DataGrid.ItemsSource" /> property is set.
         /// </summary>
         public bool AutoGenerateColumns
@@ -626,7 +626,7 @@ namespace Avalonia.Controls
             AvaloniaProperty.Register<DataGrid, bool>(nameof(AreRowDetailsFrozen));
 
         /// <summary>
-        /// Gets or sets a value that indicates whether the row details sections remain 
+        /// Gets or sets a value that indicates whether the row details sections remain
         /// fixed at the width of the display area or can scroll horizontally.
         /// </summary>
         public bool AreRowDetailsFrozen
@@ -881,7 +881,7 @@ namespace Avalonia.Controls
             {
                 int index = (int)e.NewValue;
 
-                // GetDataItem returns null if index is >= Count, we do not check newValue 
+                // GetDataItem returns null if index is >= Count, we do not check newValue
                 // against Count here to avoid enumerating through an Enumerable twice
                 // Setting SelectedItem coerces the finally value of the SelectedIndex
                 object newSelectedItem = (index < 0) ? null : DataConnection.GetDataItem(index);
@@ -1168,14 +1168,14 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Occurs one time for each public, non-static property in the bound data type when the 
-        /// <see cref="P:Avalonia.Controls.DataGrid.ItemsSource" /> property is changed and the 
+        /// Occurs one time for each public, non-static property in the bound data type when the
+        /// <see cref="P:Avalonia.Controls.DataGrid.ItemsSource" /> property is changed and the
         /// <see cref="P:Avalonia.Controls.DataGrid.AutoGenerateColumns" /> property is true.
         /// </summary>
         public event EventHandler<DataGridAutoGeneratingColumnEventArgs> AutoGeneratingColumn;
 
         /// <summary>
-        /// Occurs before a cell or row enters editing mode. 
+        /// Occurs before a cell or row enters editing mode.
         /// </summary>
         public event EventHandler<DataGridBeginningEditEventArgs> BeginningEdit;
 
@@ -1195,7 +1195,7 @@ namespace Avalonia.Controls
         public event EventHandler<DataGridCellPointerPressedEventArgs> CellPointerPressed;
 
         /// <summary>
-        /// Occurs when the <see cref="P:Avalonia.Controls.DataGridColumn.DisplayIndex" /> 
+        /// Occurs when the <see cref="P:Avalonia.Controls.DataGridColumn.DisplayIndex" />
         /// property of a column changes.
         /// </summary>
         public event EventHandler<DataGridColumnEventArgs> ColumnDisplayIndexChanged;
@@ -1218,14 +1218,14 @@ namespace Avalonia.Controls
         public event EventHandler<EventArgs> CurrentCellChanged;
 
         /// <summary>
-        /// Occurs after a <see cref="T:Avalonia.Controls.DataGridRow" /> 
+        /// Occurs after a <see cref="T:Avalonia.Controls.DataGridRow" />
         /// is instantiated, so that you can customize it before it is used.
         /// </summary>
         public event EventHandler<DataGridRowEventArgs> LoadingRow;
 
         /// <summary>
         /// Occurs when a cell in a <see cref="T:Avalonia.Controls.DataGridTemplateColumn" /> enters editing mode.
-        /// 
+        ///
         /// </summary>
         public event EventHandler<DataGridPreparingCellForEditEventArgs> PreparingCellForEdit;
 
@@ -1243,7 +1243,7 @@ namespace Avalonia.Controls
             RoutedEvent.Register<DataGrid, SelectionChangedEventArgs>(nameof(SelectionChanged), RoutingStrategies.Bubble);
 
         /// <summary>
-        /// Occurs when the <see cref="P:Avalonia.Controls.DataGrid.SelectedItem" /> or 
+        /// Occurs when the <see cref="P:Avalonia.Controls.DataGrid.SelectedItem" /> or
         /// <see cref="P:Avalonia.Controls.DataGrid.SelectedItems" /> property value changes.
         /// </summary>
         public event EventHandler<SelectionChangedEventArgs> SelectionChanged
@@ -1258,19 +1258,19 @@ namespace Avalonia.Controls
         public event EventHandler<DataGridColumnEventArgs> Sorting;
 
         /// <summary>
-        /// Occurs when a <see cref="T:Avalonia.Controls.DataGridRow" /> 
+        /// Occurs when a <see cref="T:Avalonia.Controls.DataGridRow" />
         /// object becomes available for reuse.
         /// </summary>
         public event EventHandler<DataGridRowEventArgs> UnloadingRow;
 
         /// <summary>
-        /// Occurs when a new row details template is applied to a row, so that you can customize 
+        /// Occurs when a new row details template is applied to a row, so that you can customize
         /// the details section before it is used.
         /// </summary>
         public event EventHandler<DataGridRowDetailsEventArgs> LoadingRowDetails;
 
         /// <summary>
-        /// Occurs when the <see cref="P:Avalonia.Controls.DataGrid.RowDetailsVisibilityMode" /> 
+        /// Occurs when the <see cref="P:Avalonia.Controls.DataGrid.RowDetailsVisibilityMode" />
         /// property value changes.
         /// </summary>
         public event EventHandler<DataGridRowDetailsEventArgs> RowDetailsVisibilityChanged;
@@ -1282,7 +1282,7 @@ namespace Avalonia.Controls
 
         /// <summary>
         /// Gets a collection that contains all the columns in the control.
-        /// </summary>      
+        /// </summary>
         public ObservableCollection<DataGridColumn> Columns
         {
             get
@@ -1456,7 +1456,7 @@ namespace Avalonia.Controls
         }
 
         // Height currently available for cells this value is smaller.  This height is reduced by the existence of ColumnHeaders
-        // or a horizontal scrollbar.  Layout is asynchronous so changes to the ColumnHeaders or the horizontal scrollbar are 
+        // or a horizontal scrollbar.  Layout is asynchronous so changes to the ColumnHeaders or the horizontal scrollbar are
         // not reflected immediately.
         internal double CellsHeight
         {
@@ -1555,7 +1555,7 @@ namespace Avalonia.Controls
 
         internal static double HorizontalGridLinesThickness => DATAGRID_horizontalGridLinesThickness;
 
-        // the sum of the widths in pixels of the scrolling columns preceding 
+        // the sum of the widths in pixels of the scrolling columns preceding
         // the first displayed scrolling column
         internal double HorizontalOffset
         {
@@ -2083,20 +2083,20 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Measures the children of a <see cref="T:Avalonia.Controls.DataGridRow" /> to prepare for 
-        /// arranging them during the 
-        /// <see cref="M:Avalonia.Controls.DataGridRow.ArrangeOverride(System.Windows.Size)" /> pass. 
+        /// Measures the children of a <see cref="T:Avalonia.Controls.DataGridRow" /> to prepare for
+        /// arranging them during the
+        /// <see cref="M:Avalonia.Controls.DataGridRow.ArrangeOverride(System.Windows.Size)" /> pass.
         /// </summary>
         /// <returns>
         /// The size that the <see cref="T:Avalonia.Controls.DataGridRow" /> determines it needs during layout, based on its calculations of child object allocated sizes.
         /// </returns>
         /// <param name="availableSize">
-        /// The available size that this element can give to child elements. Indicates an upper limit that 
+        /// The available size that this element can give to child elements. Indicates an upper limit that
         /// child elements should not exceed.
         /// </param>
         protected override Size MeasureOverride(Size availableSize)
         {
-            // Delay layout until after the initial measure to avoid invalid calculations when the 
+            // Delay layout until after the initial measure to avoid invalid calculations when the
             // DataGrid is not part of the visual tree
             if (!_measured)
             {
@@ -3006,7 +3006,7 @@ namespace Avalonia.Controls
         /// If the editing element has focus, this method will set focus to the DataGrid itself
         /// in order to force the element to lose focus.  It will then wait for the editing element's
         /// LostFocus event, at which point it will perform the specified action.
-        /// 
+        ///
         /// NOTE: It is important to understand that the specified action will be performed when the editing
         /// element loses focus only if this method returns true.  If it returns false, then the action
         /// will not be performed later on, and should instead be performed by the caller, if necessary.
@@ -3065,7 +3065,7 @@ namespace Avalonia.Controls
         {
             if (!_scrollingByHeight)
             {
-                // Update layout when RowDetails are expanded or collapsed, just updating the vertical scroll bar is not enough 
+                // Update layout when RowDetails are expanded or collapsed, just updating the vertical scroll bar is not enough
                 // since rows could be added or removed
                 InvalidateMeasure();
             }
@@ -3278,7 +3278,7 @@ namespace Avalonia.Controls
             {
                 // Current cell was reset because the commit deleted row(s).
                 // Since the user wants to change the current cell, we don't
-                // want to end up with no current cell. We pick the last row 
+                // want to end up with no current cell. We pick the last row
                 // in the grid which may be the 'new row'.
                 int lastSlot = LastVisibleSlot;
                 if (forCurrentCellChange &&
@@ -3336,7 +3336,7 @@ namespace Avalonia.Controls
             if (_ignoreNextScrollBarsLayout)
             {
                 _ignoreNextScrollBarsLayout = false;
-                //  
+                //
 
             }
 
@@ -3393,7 +3393,7 @@ namespace Avalonia.Controls
             }
 
             // Now cellsWidth is the width potentially available for displaying data cells.
-            // Now cellsHeight is the height potentially available for displaying data cells. 
+            // Now cellsHeight is the height potentially available for displaying data cells.
 
             bool needHorizScrollbar = false;
             bool needVertScrollbar = false;
@@ -3418,7 +3418,7 @@ namespace Avalonia.Controls
                     Debug.Assert(cellsHeight >= 0);
                     needHorizScrollbarWithoutVertScrollbar = needHorizScrollbar = true;
 
-                    if (vertScrollBarWidth > 0 && 
+                    if (vertScrollBarWidth > 0 &&
                         allowVertScrollbar && (MathUtilities.LessThanOrClose(totalVisibleWidth - cellsWidth, vertScrollBarWidth) ||
                         MathUtilities.LessThanOrClose(cellsWidth - totalVisibleFrozenWidth, vertScrollBarWidth)))
                     {
@@ -3458,7 +3458,7 @@ namespace Avalonia.Controls
                 // we compute the number of visible columns only after we set up the vertical scroll bar.
                 ComputeDisplayedColumns();
 
-                if ((vertScrollBarWidth > 0 || horizScrollBarHeight > 0) && 
+                if ((vertScrollBarWidth > 0 || horizScrollBarHeight > 0) &&
                     allowHorizScrollbar &&
                     needVertScrollbar && !needHorizScrollbar &&
                     MathUtilities.GreaterThan(totalVisibleWidth, cellsWidth) &&
@@ -3963,7 +3963,8 @@ namespace Avalonia.Controls
                         {
                             var errorList =
                                 binding.ValidationErrors
-                                       .SelectMany(ex => ValidationUtil.UnpackException(ex))
+                                       .SelectMany(ValidationUtil.UnpackException)
+                                       .Select(ValidationUtil.UnpackDataValidationException)
                                        .ToList();
 
                             DataValidationErrors.SetErrors(editingElement, errorList);
@@ -4124,7 +4125,7 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Exits editing mode without trying to commit or revert the editing, and 
+        /// Exits editing mode without trying to commit or revert the editing, and
         /// without repopulating the edited row's cell.
         /// </summary>
         //TODO TabStop
@@ -5103,9 +5104,9 @@ namespace Avalonia.Controls
         {
             if (ctrl || _editingColumnIndex == -1 || IsReadOnly)
             {
-                //Go to the next/previous control on the page when 
+                //Go to the next/previous control on the page when
                 // - Ctrl key is used
-                // - Potential current cell is not edited, or the datagrid is read-only. 
+                // - Potential current cell is not edited, or the datagrid is read-only.
                 return false;
             }
 
@@ -5516,11 +5517,11 @@ namespace Avalonia.Controls
                     //        v---v
                     //|<|_____|###|>|
                     //  ^     ^
-                    //  min   max 
+                    //  min   max
 
                     // we want to make the relative size of the thumb reflect the relative size of the viewing area
                     // viewportSize / (max + viewportSize) = cellsWidth / max
-                    // -> viewportSize = max * cellsWidth / (max - cellsWidth) 
+                    // -> viewportSize = max * cellsWidth / (max - cellsWidth)
 
                     // always zero
                     _hScrollBar.Minimum = 0;
@@ -5572,7 +5573,7 @@ namespace Avalonia.Controls
                     _hScrollBar.Maximum = 0;
                     if (_hScrollBar.IsVisible)
                     {
-                        // This will trigger a call to this method via Cells_SizeChanged for 
+                        // This will trigger a call to this method via Cells_SizeChanged for
                         // which no processing is needed.
                         _hScrollBar.IsVisible = false;
                         _ignoreNextScrollBarsLayout = true;
@@ -5591,14 +5592,14 @@ namespace Avalonia.Controls
                     //        v---v
                     //|<|_____|###|>|
                     //  ^     ^
-                    //  min   max 
+                    //  min   max
 
                     // we want to make the relative size of the thumb reflect the relative size of the viewing area
                     // viewportSize / (max + viewportSize) = cellsWidth / max
                     // -> viewportSize = max * cellsHeight / (totalVisibleHeight - cellsHeight)
                     // ->              = max * cellsHeight / (totalVisibleHeight - cellsHeight)
                     // ->              = max * cellsHeight / max
-                    // ->              = cellsHeight 
+                    // ->              = cellsHeight
 
                     // always zero
                     _vScrollBar.Minimum = 0;
@@ -5621,7 +5622,7 @@ namespace Avalonia.Controls
 
                     if (!_vScrollBar.IsVisible)
                     {
-                        // This will trigger a call to this method via Cells_SizeChanged for 
+                        // This will trigger a call to this method via Cells_SizeChanged for
                         // which no processing is needed.
                         _vScrollBar.IsVisible = true;
                         if (_vScrollBar.DesiredSize.Width == 0)
@@ -5637,7 +5638,7 @@ namespace Avalonia.Controls
                     _vScrollBar.Maximum = 0;
                     if (_vScrollBar.IsVisible)
                     {
-                        // This will trigger a call to this method via Cells_SizeChanged for 
+                        // This will trigger a call to this method via Cells_SizeChanged for
                         // which no processing is needed.
                         _vScrollBar.IsVisible = false;
                         _ignoreNextScrollBarsLayout = true;
@@ -5660,8 +5661,8 @@ namespace Avalonia.Controls
             Debug.Assert(slot >= 0);
 
             // Before changing selection, check if the current cell needs to be committed, and
-            // check if the current row needs to be committed. If any of those two operations are required and fail, 
-            // do not change selection, and do not change current cell. 
+            // check if the current row needs to be committed. If any of those two operations are required and fail,
+            // do not change selection, and do not change current cell.
 
             bool wasInEdit = EditingColumnIndex != -1;
 
diff --git a/src/Avalonia.Controls.DataGrid/Utils/ValidationUtil.cs b/src/Avalonia.Controls.DataGrid/Utils/ValidationUtil.cs
index e1ecb2c562..c36d9708c1 100644
--- a/src/Avalonia.Controls.DataGrid/Utils/ValidationUtil.cs
+++ b/src/Avalonia.Controls.DataGrid/Utils/ValidationUtil.cs
@@ -80,19 +80,24 @@ namespace Avalonia.Controls.Utils
         {
             if (exception != null)
             {
-                var aggregate = exception as AggregateException;
-                var exceptions = aggregate == null ?
-                    (IEnumerable<Exception>)new[] { exception } :
-                    aggregate.InnerExceptions;
-                var filtered = exceptions.Where(x => !(x is BindingChainException)).ToList();
+                var exceptions = exception is AggregateException aggregate ?
+                    aggregate.InnerExceptions :
+                    (IEnumerable<Exception>)new[] { exception };
 
-                if (filtered.Count > 0)
-                {
-                    return filtered;
-                }
+                return exceptions.Where(x => !(x is BindingChainException)).ToList();
             }
 
-            return null;
+            return Array.Empty<Exception>();
+        }
+
+        public static object UnpackDataValidationException(Exception exception)
+        {
+            if (exception is DataValidationException dataValidationException)
+            {
+                return dataValidationException.ErrorData;
+            }
+
+            return exception;
         }
 
         /// <summary>

From d9a161d00bf8dc8865ba08f928a4743c29a09414 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sat, 2 Jan 2021 02:50:01 -0500
Subject: [PATCH 14/23] Add HorizontalContentAlignment/VerticalContentAlignment
 props to NumericUpDown

---
 .../NumericUpDown/NumericUpDown.cs            | 33 +++++++++++++++++++
 .../NumericUpDown.xaml                        |  4 ++-
 .../Controls/NumericUpDown.xaml               |  7 ++--
 3 files changed, 41 insertions(+), 3 deletions(-)

diff --git a/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs b/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
index aae041071d..b6b71644a3 100644
--- a/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
+++ b/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
@@ -6,6 +6,7 @@ using Avalonia.Controls.Primitives;
 using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
 using Avalonia.Threading;
 using Avalonia.Utilities;
 
@@ -105,6 +106,19 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<string> WatermarkProperty =
             AvaloniaProperty.Register<NumericUpDown, string>(nameof(Watermark));
 
+
+        /// <summary>
+        /// Defines the <see cref="HorizontalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<HorizontalAlignment> HorizontalContentAlignmentProperty =
+            ContentControl.HorizontalContentAlignmentProperty.AddOwner<NumericUpDown>();
+
+        /// <summary>
+        /// Defines the <see cref="VerticalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
+            ContentControl.VerticalContentAlignmentProperty.AddOwner<NumericUpDown>();
+
         private IDisposable _textBoxTextChangedSubscription;
 
         private double _value;
@@ -256,6 +270,25 @@ namespace Avalonia.Controls
             set { SetValue(WatermarkProperty, value); }
         }
 
+
+        /// <summary>
+        /// Gets or sets the horizontal alignment of the content within the control.
+        /// </summary>
+        public HorizontalAlignment HorizontalContentAlignment
+        {
+            get => GetValue(HorizontalContentAlignmentProperty);
+            set => SetValue(HorizontalContentAlignmentProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the vertical alignment of the content within the control.
+        /// </summary>
+        public VerticalAlignment VerticalContentAlignment
+        {
+            get => GetValue(VerticalContentAlignmentProperty);
+            set => SetValue(VerticalContentAlignmentProperty, value);
+        }
+
         /// <summary>
         /// Initializes new instance of <see cref="NumericUpDown"/> class.
         /// </summary>
diff --git a/src/Avalonia.Themes.Default/NumericUpDown.xaml b/src/Avalonia.Themes.Default/NumericUpDown.xaml
index 24cbb62908..025e822404 100644
--- a/src/Avalonia.Themes.Default/NumericUpDown.xaml
+++ b/src/Avalonia.Themes.Default/NumericUpDown.xaml
@@ -23,6 +23,8 @@
                    Watermark="{TemplateBinding Watermark}"
                    DataValidationErrors.Errors="{TemplateBinding (DataValidationErrors.Errors)}"
                    IsReadOnly="{TemplateBinding IsReadOnly}"
+                   VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                    Text="{TemplateBinding Text}"
                    AcceptsReturn="False"
                    TextWrapping="NoWrap">
@@ -35,4 +37,4 @@
     <Setter Property="Margin" Value="4"/>
     <Setter Property="MinWidth" Value="20"/>
   </Style>
-</Styles>
\ No newline at end of file
+</Styles>
diff --git a/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml b/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
index 1da48ebd8a..288b3ccee6 100644
--- a/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/NumericUpDown.xaml
@@ -1,8 +1,7 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Design.PreviewWith>
-    <Border Padding="20"
-            Background="Black">
+    <Border Padding="20">
       <StackPanel Spacing="20">
         <NumericUpDown Minimum="0"
                        Maximum="10"
@@ -13,6 +12,8 @@
                        Maximum="10"
                        Increment="0.5"
                        Width="150"
+                       VerticalContentAlignment="Center"
+                       HorizontalContentAlignment="Center"
                        ButtonSpinnerLocation="Left"
                        Watermark="Enter text" />
       </StackPanel>
@@ -48,6 +49,8 @@
                    Padding="{TemplateBinding Padding}"
                    Watermark="{TemplateBinding Watermark}"
                    IsReadOnly="{TemplateBinding IsReadOnly}"
+                   VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                    Text="{TemplateBinding Text}"
                    AcceptsReturn="False"
                    TextWrapping="NoWrap" />

From 107b4d83fdc026dcfc3fe692c8ae683341b11126 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sat, 2 Jan 2021 02:50:10 -0500
Subject: [PATCH 15/23] Add HorizontalContentAlignment/VerticalContentAlignment
 props to CalendarDatePicker

---
 .../Calendar/CalendarDatePicker.cs            | 32 +++++++++++++++++++
 .../CalendarDatePicker.xaml                   |  2 ++
 .../Controls/CalendarDatePicker.xaml          |  8 +++--
 3 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs b/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
index 7c259f0a09..af3fdbd662 100644
--- a/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
+++ b/src/Avalonia.Controls/Calendar/CalendarDatePicker.cs
@@ -11,6 +11,7 @@ using Avalonia.Controls.Primitives;
 using Avalonia.Data;
 using Avalonia.Input;
 using Avalonia.Interactivity;
+using Avalonia.Layout;
 
 namespace Avalonia.Controls
 {
@@ -209,6 +210,18 @@ namespace Avalonia.Controls
             TextBox.UseFloatingWatermarkProperty.AddOwner<CalendarDatePicker>();
 
 
+        /// <summary>
+        /// Defines the <see cref="HorizontalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<HorizontalAlignment> HorizontalContentAlignmentProperty =
+            ContentControl.HorizontalContentAlignmentProperty.AddOwner<CalendarDatePicker>();
+
+        /// <summary>
+        /// Defines the <see cref="VerticalContentAlignment"/> property.
+        /// </summary>
+        public static readonly StyledProperty<VerticalAlignment> VerticalContentAlignmentProperty =
+            ContentControl.VerticalContentAlignmentProperty.AddOwner<CalendarDatePicker>();
+
         /// <summary>
         /// Gets or sets the date to display.
         /// </summary>
@@ -364,6 +377,25 @@ namespace Avalonia.Controls
             set { SetValue(UseFloatingWatermarkProperty, value); }
         }
 
+
+        /// <summary>
+        /// Gets or sets the horizontal alignment of the content within the control.
+        /// </summary>
+        public HorizontalAlignment HorizontalContentAlignment
+        {
+            get => GetValue(HorizontalContentAlignmentProperty);
+            set => SetValue(HorizontalContentAlignmentProperty, value);
+        }
+
+        /// <summary>
+        /// Gets or sets the vertical alignment of the content within the control.
+        /// </summary>
+        public VerticalAlignment VerticalContentAlignment
+        {
+            get => GetValue(VerticalContentAlignmentProperty);
+            set => SetValue(VerticalContentAlignmentProperty, value);
+        }
+
         /// <summary>
         /// Occurs when the drop-down
         /// <see cref="T:Avalonia.Controls.Calendar" /> is closed.
diff --git a/src/Avalonia.Themes.Default/CalendarDatePicker.xaml b/src/Avalonia.Themes.Default/CalendarDatePicker.xaml
index bc1aba1a03..aab7d06c46 100644
--- a/src/Avalonia.Themes.Default/CalendarDatePicker.xaml
+++ b/src/Avalonia.Themes.Default/CalendarDatePicker.xaml
@@ -93,6 +93,8 @@
                    Watermark="{TemplateBinding Watermark}"
                    UseFloatingWatermark="{TemplateBinding UseFloatingWatermark}"
                    DataValidationErrors.Errors="{TemplateBinding (DataValidationErrors.Errors)}"
+                   VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                    Grid.Column="0"/>
 
           <Button Name="PART_Button"
diff --git a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
index 75343ebb4a..c902e371fb 100644
--- a/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/CalendarDatePicker.xaml
@@ -9,8 +9,10 @@
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:sys="clr-namespace:System;assembly=netstandard">
   <Design.PreviewWith>
-    <Border Margin="20">
-      <CalendarDatePicker/>
+    <Border Margin="20, 20, 20, 200">
+      <CalendarDatePicker Width="200"
+                          VerticalContentAlignment="Center"
+                          HorizontalContentAlignment="Center" />
     </Border>
   </Design.PreviewWith>
 
@@ -104,6 +106,8 @@
                    Watermark="{TemplateBinding Watermark}"
                    UseFloatingWatermark="{TemplateBinding UseFloatingWatermark}"
                    DataValidationErrors.Errors="{TemplateBinding (DataValidationErrors.Errors)}"
+                   VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                   HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                    Grid.Column="0"/>
 
           <Button Name="PART_Button"

From 5403c743441d476f2577c3d3c1b4c91e1e5a0477 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 3 Jan 2021 03:31:15 -0500
Subject: [PATCH 16/23] Recalculate ToolTip position on Offset/Placement props
 changed

---
 src/Avalonia.Controls/ToolTip.cs | 40 +++++++++++++++++++++++++-------
 1 file changed, 31 insertions(+), 9 deletions(-)

diff --git a/src/Avalonia.Controls/ToolTip.cs b/src/Avalonia.Controls/ToolTip.cs
index 71bd0726d4..ab507d07a2 100644
--- a/src/Avalonia.Controls/ToolTip.cs
+++ b/src/Avalonia.Controls/ToolTip.cs
@@ -1,3 +1,4 @@
+#nullable enable
 using System;
 using System.Reactive.Linq;
 using Avalonia.Controls.Metadata;
@@ -21,8 +22,8 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the ToolTip.Tip attached property.
         /// </summary>
-        public static readonly AttachedProperty<object> TipProperty =
-            AvaloniaProperty.RegisterAttached<ToolTip, Control, object>("Tip");
+        public static readonly AttachedProperty<object?> TipProperty =
+            AvaloniaProperty.RegisterAttached<ToolTip, Control, object?>("Tip");
 
         /// <summary>
         /// Defines the ToolTip.IsOpen attached property.
@@ -57,10 +58,10 @@ namespace Avalonia.Controls
         /// <summary>
         /// Stores the current <see cref="ToolTip"/> instance in the control.
         /// </summary>
-        internal static readonly AttachedProperty<ToolTip> ToolTipProperty =
-            AvaloniaProperty.RegisterAttached<ToolTip, Control, ToolTip>("ToolTip");
+        internal static readonly AttachedProperty<ToolTip?> ToolTipProperty =
+            AvaloniaProperty.RegisterAttached<ToolTip, Control, ToolTip?>("ToolTip");
 
-        private IPopupHost _popup;
+        private IPopupHost? _popup;
 
         /// <summary>
         /// Initializes static members of the <see cref="ToolTip"/> class.
@@ -70,6 +71,10 @@ namespace Avalonia.Controls
             TipProperty.Changed.Subscribe(ToolTipService.Instance.TipChanged);
             IsOpenProperty.Changed.Subscribe(ToolTipService.Instance.TipOpenChanged);
             IsOpenProperty.Changed.Subscribe(IsOpenChanged);
+
+            HorizontalOffsetProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
+            VerticalOffsetProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
+            PlacementProperty.Changed.Subscribe(RecalculatePositionOnPropertyChanged);
         }
 
         /// <summary>
@@ -79,7 +84,7 @@ namespace Avalonia.Controls
         /// <returns>
         /// The content to be displayed in the control's tooltip.
         /// </returns>
-        public static object GetTip(Control element)
+        public static object? GetTip(Control element)
         {
             return element.GetValue(TipProperty);
         }
@@ -89,7 +94,7 @@ namespace Avalonia.Controls
         /// </summary>
         /// <param name="element">The control to get the property from.</param>
         /// <param name="value">The content to be displayed in the control's tooltip.</param>
-        public static void SetTip(Control element, object value)
+        public static void SetTip(Control element, object? value)
         {
             element.SetValue(TipProperty, value);
         }
@@ -207,8 +212,8 @@ namespace Avalonia.Controls
         private static void IsOpenChanged(AvaloniaPropertyChangedEventArgs e)
         {
             var control = (Control)e.Sender;
-            var newValue = (bool)e.NewValue;
-            ToolTip toolTip;
+            var newValue = (bool)e.NewValue!;
+            ToolTip? toolTip;
 
             if (newValue)
             {
@@ -235,6 +240,23 @@ namespace Avalonia.Controls
             toolTip?.UpdatePseudoClasses(newValue);
         }
 
+        private static void RecalculatePositionOnPropertyChanged(AvaloniaPropertyChangedEventArgs args)
+        {
+            var control = (Control)args.Sender;
+            var tooltip = control.GetValue(ToolTipProperty);
+            if (tooltip == null)
+            {
+                return;
+            }
+
+            tooltip.RecalculatePosition(control);
+        }
+
+        internal void RecalculatePosition(Control control)
+        {
+            _popup?.ConfigurePosition(control, GetPlacement(control), new Point(GetHorizontalOffset(control), GetVerticalOffset(control)));
+        }
+
         private void Open(Control control)
         {
             Close();

From 3140c1c15e14cdf4eed536e307b5f0af164153ba Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 3 Jan 2021 03:31:31 -0500
Subject: [PATCH 17/23] Recalculate ToolTip position on target bounds changed

---
 src/Avalonia.Controls/ToolTipService.cs | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/Avalonia.Controls/ToolTipService.cs b/src/Avalonia.Controls/ToolTipService.cs
index 341ab2fe81..cd0fad1997 100644
--- a/src/Avalonia.Controls/ToolTipService.cs
+++ b/src/Avalonia.Controls/ToolTipService.cs
@@ -28,12 +28,14 @@ namespace Avalonia.Controls
             {
                 control.PointerEnter -= ControlPointerEnter;
                 control.PointerLeave -= ControlPointerLeave;
+                control.PropertyChanged -= Control_PropertyChanged;
             }
 
             if (e.NewValue != null)
             {
                 control.PointerEnter += ControlPointerEnter;
                 control.PointerLeave += ControlPointerLeave;
+                control.PropertyChanged += Control_PropertyChanged;
             }
 
             if (ToolTip.GetIsOpen(control) && e.NewValue != e.OldValue && !(e.NewValue is ToolTip))
@@ -97,6 +99,17 @@ namespace Avalonia.Controls
             Close(control);
         }
 
+        private void Control_PropertyChanged(object sender, AvaloniaPropertyChangedEventArgs e)
+        {
+            var control = (Control)sender;
+
+            if (e.Property == Visual.TransformedBoundsProperty)
+            {
+                var toolTip = control.GetValue(ToolTip.ToolTipProperty);
+                toolTip?.RecalculatePosition(control);
+            }
+        }
+
         private void StartShowTimer(int showDelay, Control control)
         {
             _timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(showDelay) };

From 2cac9980e1ed21c4413e795394538bb2f039e0a6 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 3 Jan 2021 03:31:51 -0500
Subject: [PATCH 18/23] Update tooltip samples

---
 samples/ControlCatalog/Pages/SliderPage.xaml  | 14 ++++++++++
 samples/ControlCatalog/Pages/ToolTipPage.xaml | 27 ++++++++++++++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/samples/ControlCatalog/Pages/SliderPage.xaml b/samples/ControlCatalog/Pages/SliderPage.xaml
index b3f32ed421..eeb198976b 100644
--- a/samples/ControlCatalog/Pages/SliderPage.xaml
+++ b/samples/ControlCatalog/Pages/SliderPage.xaml
@@ -22,6 +22,20 @@
                 IsSnapToTickEnabled="True"
                 Ticks="0,20,25,40,75,100"
                 Width="300" />
+        <Slider Name="SliderWithTooltip"
+                Value="0"
+                Minimum="0"
+                Maximum="100"
+                Width="300">
+          <Slider.Styles>
+            <Style Selector="Slider /template/ Thumb">
+              <Setter Property="ToolTip.Tip" Value="{Binding $parent[Slider].Value, Mode=OneWay, StringFormat='Value \{0:f\}'}" />
+              <Setter Property="ToolTip.Placement" Value="Top" />
+              <Setter Property="ToolTip.VerticalOffset" Value="-10" />
+              <Setter Property="ToolTip.HorizontalOffset" Value="-30" />
+            </Style>
+          </Slider.Styles>
+        </Slider>
         <Slider Value="0"
                 Minimum="0"
                 Maximum="100"
diff --git a/samples/ControlCatalog/Pages/ToolTipPage.xaml b/samples/ControlCatalog/Pages/ToolTipPage.xaml
index ec073d48a9..de23c7a169 100644
--- a/samples/ControlCatalog/Pages/ToolTipPage.xaml
+++ b/samples/ControlCatalog/Pages/ToolTipPage.xaml
@@ -6,7 +6,7 @@
         <TextBlock Classes="h1">ToolTip</TextBlock>
         <TextBlock Classes="h2">A control which pops up a hint when a control is hovered</TextBlock>
 
-        <Grid RowDefinitions="Auto,Auto"
+        <Grid RowDefinitions="Auto,Auto,Auto"
               ColumnDefinitions="Auto,Auto"
               Margin="0,16,0,0"
               HorizontalAlignment="Center">
@@ -38,6 +38,31 @@
                 </ToolTip.Tip>
                 <TextBlock>ToolTip bottom placement</TextBlock>
             </Border>
+            <Border Grid.Row="2"
+                    Grid.ColumnSpan="2"
+                    Background="{DynamicResource SystemAccentColor}"
+                    Margin="5"
+                    Padding="50"
+                    ToolTip.Tip="Hello"
+                    ToolTip.Placement="Top">
+              <Border.Styles>
+                <Style Selector="Border">
+                  <Style.Animations>
+                    <Animation Duration="0:0:2" IterationCount="Infinite">
+                      <KeyFrame KeyTime="0:0:0">
+                        <Setter Property="ToolTip.HorizontalOffset" Value="0" />
+                        <Setter Property="ToolTip.VerticalOffset" Value="-50" />
+                      </KeyFrame>
+                      <KeyFrame KeyTime="0:0:2" >
+                        <Setter Property="ToolTip.HorizontalOffset" Value="100" />
+                        <Setter Property="ToolTip.VerticalOffset" Value="50" />
+                      </KeyFrame>
+                    </Animation>
+                  </Style.Animations>
+                </Style>
+              </Border.Styles>
+              <TextBlock>Moving offset</TextBlock>
+            </Border>
         </Grid>
     </StackPanel>
 </UserControl>

From ca947cc912288c464ec5e30e7c21d7b94328dac8 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 3 Jan 2021 04:04:19 -0500
Subject: [PATCH 19/23] Use Bounds instead of TransformedBoundsProperty to
 recalculate ToolTip position

---
 src/Avalonia.Controls/ToolTipService.cs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Avalonia.Controls/ToolTipService.cs b/src/Avalonia.Controls/ToolTipService.cs
index cd0fad1997..d40a116dd5 100644
--- a/src/Avalonia.Controls/ToolTipService.cs
+++ b/src/Avalonia.Controls/ToolTipService.cs
@@ -103,7 +103,7 @@ namespace Avalonia.Controls
         {
             var control = (Control)sender;
 
-            if (e.Property == Visual.TransformedBoundsProperty)
+            if (e.Property == Visual.BoundsProperty)
             {
                 var toolTip = control.GetValue(ToolTip.ToolTipProperty);
                 toolTip?.RecalculatePosition(control);

From ee717223f002832853d93e5d7d2b734e9431ca4d Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 3 Jan 2021 16:18:31 -0500
Subject: [PATCH 20/23] Use EffectiveViewportChanged instead of subscribing on
 PropertyChanged

---
 src/Avalonia.Controls/ToolTipService.cs | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/src/Avalonia.Controls/ToolTipService.cs b/src/Avalonia.Controls/ToolTipService.cs
index d40a116dd5..9e0bf60f42 100644
--- a/src/Avalonia.Controls/ToolTipService.cs
+++ b/src/Avalonia.Controls/ToolTipService.cs
@@ -28,14 +28,12 @@ namespace Avalonia.Controls
             {
                 control.PointerEnter -= ControlPointerEnter;
                 control.PointerLeave -= ControlPointerLeave;
-                control.PropertyChanged -= Control_PropertyChanged;
             }
 
             if (e.NewValue != null)
             {
                 control.PointerEnter += ControlPointerEnter;
                 control.PointerLeave += ControlPointerLeave;
-                control.PropertyChanged += Control_PropertyChanged;
             }
 
             if (ToolTip.GetIsOpen(control) && e.NewValue != e.OldValue && !(e.NewValue is ToolTip))
@@ -53,10 +51,12 @@ namespace Avalonia.Controls
             if (e.OldValue is false && e.NewValue is true)
             {
                 control.DetachedFromVisualTree += ControlDetaching;
+                control.EffectiveViewportChanged += ControlEffectiveViewportChanged;
             }
             else if(e.OldValue is true && e.NewValue is false)
             {
                 control.DetachedFromVisualTree -= ControlDetaching;
+                control.EffectiveViewportChanged -= ControlEffectiveViewportChanged;
             }
         }
         
@@ -64,6 +64,7 @@ namespace Avalonia.Controls
         {
             var control = (Control)sender;
             control.DetachedFromVisualTree -= ControlDetaching;
+            control.EffectiveViewportChanged -= ControlEffectiveViewportChanged;
             Close(control);
         }
 
@@ -99,15 +100,11 @@ namespace Avalonia.Controls
             Close(control);
         }
 
-        private void Control_PropertyChanged(object sender, AvaloniaPropertyChangedEventArgs e)
+        private void ControlEffectiveViewportChanged(object sender, Layout.EffectiveViewportChangedEventArgs e)
         {
             var control = (Control)sender;
-
-            if (e.Property == Visual.BoundsProperty)
-            {
-                var toolTip = control.GetValue(ToolTip.ToolTipProperty);
-                toolTip?.RecalculatePosition(control);
-            }
+            var toolTip = control.GetValue(ToolTip.ToolTipProperty);
+            toolTip?.RecalculatePosition(control);
         }
 
         private void StartShowTimer(int showDelay, Control control)

From 90344d4c03fd0b983fd0de59f9a4c4905dfc5057 Mon Sep 17 00:00:00 2001
From: Andrey Kunchev <donandren@gmail.com>
Date: Mon, 4 Jan 2021 11:39:11 +0200
Subject: [PATCH 21/23] fix #5217 native immediate crash on 0,0 rendering
 popup/window macos

---
 native/Avalonia.Native/src/OSX/rendertarget.mm | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/native/Avalonia.Native/src/OSX/rendertarget.mm b/native/Avalonia.Native/src/OSX/rendertarget.mm
index 00b6dab219..9ec08853e1 100644
--- a/native/Avalonia.Native/src/OSX/rendertarget.mm
+++ b/native/Avalonia.Native/src/OSX/rendertarget.mm
@@ -111,7 +111,11 @@
         if(_renderbuffer != 0)
             glDeleteRenderbuffers(1, &_renderbuffer);
     }
-    CFRelease(surface);
+
+    if(surface != nullptr)
+    {
+        CFRelease(surface);
+    }
 }
 @end
 

From 78c2415462c98ae4c3fbef100a005e067fe13920 Mon Sep 17 00:00:00 2001
From: Andrey Kunchev <donandren@gmail.com>
Date: Mon, 4 Jan 2021 11:39:11 +0200
Subject: [PATCH 22/23] ensure we have valid surface with min size (1,1)

---
 native/Avalonia.Native/src/OSX/rendertarget.mm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/native/Avalonia.Native/src/OSX/rendertarget.mm b/native/Avalonia.Native/src/OSX/rendertarget.mm
index 9ec08853e1..b2d4341bb9 100644
--- a/native/Avalonia.Native/src/OSX/rendertarget.mm
+++ b/native/Avalonia.Native/src/OSX/rendertarget.mm
@@ -149,6 +149,12 @@ static IAvnGlSurfaceRenderTarget* CreateGlRenderTarget(IOSurfaceRenderTarget* ta
 }
 
 - (void)resize:(AvnPixelSize)size withScale: (float) scale{
+
+    if(size.Height <= 0)
+        size.Height = 1;
+    if(size.Width <= 0)
+        size.Width = 1;
+
     @synchronized (lock) {
         if(surface == nil
            || surface->size.Width != size.Width

From d34a2c6721ad406afa500ee7f47d01da99288ac9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Pedro?= <jpedrolmail@gmail.com>
Date: Fri, 15 Jan 2021 11:08:28 +0000
Subject: [PATCH 23/23] Use SKFontManager for typeface matching. Handle null
 typeface because of Android.

---
 src/Skia/Avalonia.Skia/FontManagerImpl.cs | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/Skia/Avalonia.Skia/FontManagerImpl.cs b/src/Skia/Avalonia.Skia/FontManagerImpl.cs
index 62ec39346a..178ee8c544 100644
--- a/src/Skia/Avalonia.Skia/FontManagerImpl.cs
+++ b/src/Skia/Avalonia.Skia/FontManagerImpl.cs
@@ -109,20 +109,23 @@ namespace Avalonia.Skia
             if (typeface.FontFamily.Key == null)
             {
                 var defaultName = SKTypeface.Default.FamilyName;
+                var fontStyle = new SKFontStyle((SKFontStyleWeight)typeface.Weight, SKFontStyleWidth.Normal, (SKFontStyleSlant)typeface.Style);
 
                 foreach (var familyName in typeface.FontFamily.FamilyNames)
                 {
-                    skTypeface = SKTypeface.FromFamilyName(familyName, (SKFontStyleWeight)typeface.Weight,
-                        SKFontStyleWidth.Normal, (SKFontStyleSlant)typeface.Style);
+                    skTypeface = _skFontManager.MatchFamily(familyName, fontStyle);
 
-                    if (!skTypeface.FamilyName.Equals(familyName, StringComparison.Ordinal) &&
-                        defaultName.Equals(skTypeface.FamilyName, StringComparison.Ordinal))
+                    if (skTypeface is null
+                        || (!skTypeface.FamilyName.Equals(familyName, StringComparison.Ordinal)
+                            && defaultName.Equals(skTypeface.FamilyName, StringComparison.Ordinal)))
                     {
                         continue;
                     }
 
                     break;
                 }
+
+                skTypeface ??= _skFontManager.MatchTypeface(SKTypeface.Default, fontStyle);
             }
             else
             {