From b7bb635c80cfedd2951b5daced726b9174ef4e12 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 24 Oct 2021 13:24:37 -0400
Subject: [PATCH 1/7] Add missing background to the presenters and popup roots

---
 src/Avalonia.Themes.Default/FlyoutPresenter.xaml     | 2 +-
 src/Avalonia.Themes.Default/MenuFlyoutPresenter.xaml | 2 +-
 src/Avalonia.Themes.Default/PopupRoot.xaml           | 1 +
 src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml   | 1 +
 4 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Themes.Default/FlyoutPresenter.xaml b/src/Avalonia.Themes.Default/FlyoutPresenter.xaml
index 95f48e6c29..3bc5e085ff 100644
--- a/src/Avalonia.Themes.Default/FlyoutPresenter.xaml
+++ b/src/Avalonia.Themes.Default/FlyoutPresenter.xaml
@@ -2,7 +2,7 @@
   <Style Selector="FlyoutPresenter">
     <Setter Property="HorizontalContentAlignment" Value="Stretch" />
     <Setter Property="VerticalContentAlignment" Value="Stretch" />
-    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
     <Setter Property="BorderThickness" Value="1" />
     <Setter Property="Padding" Value="4" />
diff --git a/src/Avalonia.Themes.Default/MenuFlyoutPresenter.xaml b/src/Avalonia.Themes.Default/MenuFlyoutPresenter.xaml
index 0d246ac12c..d56b46b17c 100644
--- a/src/Avalonia.Themes.Default/MenuFlyoutPresenter.xaml
+++ b/src/Avalonia.Themes.Default/MenuFlyoutPresenter.xaml
@@ -1,6 +1,6 @@
 <Styles xmlns="https://github.com/avaloniaui">
   <Style Selector="MenuFlyoutPresenter">
-    <Setter Property="Background" Value="Transparent" />
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}" />
     <Setter Property="BorderThickness" Value="1" />
     <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Auto" />
diff --git a/src/Avalonia.Themes.Default/PopupRoot.xaml b/src/Avalonia.Themes.Default/PopupRoot.xaml
index b9f68c8421..ef6574c142 100644
--- a/src/Avalonia.Themes.Default/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Default/PopupRoot.xaml
@@ -1,6 +1,7 @@
 <Style xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Selector="PopupRoot">
+  <Setter Property="Background" Value="Transparent"/>
   <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
   <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}"/>
   <Setter Property="FontFamily" Value="{x:Static FontFamily.Default}" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml b/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
index f282586908..1d9e94260d 100644
--- a/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
@@ -1,6 +1,7 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="PopupRoot">
+    <Setter Property="Background" Value="Transparent"/>
     <Setter Property="TransparencyLevelHint" Value="Transparent" />
     <Setter Property="Foreground" Value="{DynamicResource SystemControlForegroundBaseHighBrush}"/>
     <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}"/>

From 165e3a14a42fac6c213a1b53f52335ddcf20fece Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 24 Oct 2021 13:25:06 -0400
Subject: [PATCH 2/7] Remove or add  TransparencyLevelHint where it should be

---
 .../OverlayPopupHost.xaml                       | 17 +++++++----------
 src/Avalonia.Themes.Default/PopupRoot.xaml      |  1 +
 .../Controls/OverlayPopupHost.xaml              | 17 +++++++----------
 3 files changed, 15 insertions(+), 20 deletions(-)

diff --git a/src/Avalonia.Themes.Default/OverlayPopupHost.xaml b/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
index f054280e06..5f24388b6e 100644
--- a/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
+++ b/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
@@ -8,16 +8,13 @@
   <Setter Property="FontStyle" Value="Normal" />
   <Setter Property="Template">
     <ControlTemplate>
-      <Panel>
-        <Border Name="PART_TransparencyFallback" IsHitTestVisible="False" />
-        <VisualLayerManager IsPopup="True">
-          <ContentPresenter Name="PART_ContentPresenter"
-                            Background="{TemplateBinding Background}"
-                            ContentTemplate="{TemplateBinding ContentTemplate}"
-                            Content="{TemplateBinding Content}"
-                            Padding="{TemplateBinding Padding}"/>
-        </VisualLayerManager>
-      </Panel>
+      <VisualLayerManager IsPopup="True">
+        <ContentPresenter Name="PART_ContentPresenter"
+                          Background="{TemplateBinding Background}"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
+                          Padding="{TemplateBinding Padding}"/>
+      </VisualLayerManager>
     </ControlTemplate>
   </Setter>
 </Style>
diff --git a/src/Avalonia.Themes.Default/PopupRoot.xaml b/src/Avalonia.Themes.Default/PopupRoot.xaml
index ef6574c142..92344fb130 100644
--- a/src/Avalonia.Themes.Default/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Default/PopupRoot.xaml
@@ -2,6 +2,7 @@
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Selector="PopupRoot">
   <Setter Property="Background" Value="Transparent"/>
+  <Setter Property="TransparencyLevelHint" Value="Transparent" />
   <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
   <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}"/>
   <Setter Property="FontFamily" Value="{x:Static FontFamily.Default}" />
diff --git a/src/Avalonia.Themes.Fluent/Controls/OverlayPopupHost.xaml b/src/Avalonia.Themes.Fluent/Controls/OverlayPopupHost.xaml
index c0c56f2ff3..5d9d04d218 100644
--- a/src/Avalonia.Themes.Fluent/Controls/OverlayPopupHost.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/OverlayPopupHost.xaml
@@ -6,16 +6,13 @@
   <Setter Property="FontStyle" Value="Normal" />
   <Setter Property="Template">
     <ControlTemplate>
-      <Panel>
-        <Border Name="PART_TransparencyFallback" IsHitTestVisible="False" />
-        <VisualLayerManager IsPopup="True">
-          <ContentPresenter Name="PART_ContentPresenter"
-                            Background="{TemplateBinding Background}"
-                            ContentTemplate="{TemplateBinding ContentTemplate}"
-                            Content="{TemplateBinding Content}"
-                            Padding="{TemplateBinding Padding}"/>
-        </VisualLayerManager>
-      </Panel>
+      <VisualLayerManager IsPopup="True">
+        <ContentPresenter Name="PART_ContentPresenter"
+                          Background="{TemplateBinding Background}"
+                          ContentTemplate="{TemplateBinding ContentTemplate}"
+                          Content="{TemplateBinding Content}"
+                          Padding="{TemplateBinding Padding}"/>
+      </VisualLayerManager>
     </ControlTemplate>
   </Setter>
 </Style>

From 069f299b8a78e3bcadd52bb5bfc18429ff7fe4a0 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 24 Oct 2021 13:25:17 -0400
Subject: [PATCH 3/7] Remove duplicated CornerRadius

---
 src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs b/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
index 3a45c85c70..b1d3df9ddd 100644
--- a/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
+++ b/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
@@ -8,15 +8,6 @@ namespace Avalonia.Controls
 {
     public class MenuFlyoutPresenter : MenuBase
     {
-        public static readonly StyledProperty<CornerRadius> CornerRadiusProperty =
-            Border.CornerRadiusProperty.AddOwner<FlyoutPresenter>();
-
-        public CornerRadius CornerRadius
-        {
-            get => GetValue(CornerRadiusProperty);
-            set => SetValue(CornerRadiusProperty, value);
-        }
-
         public MenuFlyoutPresenter()
             :base(new DefaultMenuInteractionHandler(true))
         {

From 3bf4acce30a5270fe954c987ff4055567e45bacd Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Sun, 24 Oct 2021 13:32:13 -0400
Subject: [PATCH 4/7] Add missing background to the popup controls

---
 src/Avalonia.Themes.Default/AutoCompleteBox.xaml | 3 ++-
 src/Avalonia.Themes.Default/ComboBox.xaml        | 3 ++-
 src/Avalonia.Themes.Default/ContextMenu.xaml     | 1 +
 src/Avalonia.Themes.Default/MenuItem.xaml        | 4 ++--
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/Avalonia.Themes.Default/AutoCompleteBox.xaml b/src/Avalonia.Themes.Default/AutoCompleteBox.xaml
index fe4cd48e72..fac8ca51f8 100644
--- a/src/Avalonia.Themes.Default/AutoCompleteBox.xaml
+++ b/src/Avalonia.Themes.Default/AutoCompleteBox.xaml
@@ -21,7 +21,8 @@
                  MaxHeight="{TemplateBinding MaxDropDownHeight}"
                  PlacementTarget="{TemplateBinding}"
                  IsLightDismissEnabled="True">
-            <Border BorderBrush="{DynamicResource ThemeBorderMidBrush}"
+            <Border Background="{DynamicResource ThemeBackgroundBrush}"
+                    BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                     BorderThickness="1">
               <ListBox Name="PART_SelectingItemsControl"
                        BorderThickness="0"
diff --git a/src/Avalonia.Themes.Default/ComboBox.xaml b/src/Avalonia.Themes.Default/ComboBox.xaml
index 754aadac83..262f63e2d2 100644
--- a/src/Avalonia.Themes.Default/ComboBox.xaml
+++ b/src/Avalonia.Themes.Default/ComboBox.xaml
@@ -69,7 +69,8 @@
                    MaxHeight="{TemplateBinding MaxDropDownHeight}"
                    PlacementTarget="{TemplateBinding}"
                    IsLightDismissEnabled="True">
-              <Border BorderBrush="{DynamicResource ThemeBorderMidBrush}"
+              <Border Background="{DynamicResource ThemeBackgroundBrush}"
+                      BorderBrush="{DynamicResource ThemeBorderMidBrush}"                      
                       BorderThickness="1">
                 <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
                               VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}">
diff --git a/src/Avalonia.Themes.Default/ContextMenu.xaml b/src/Avalonia.Themes.Default/ContextMenu.xaml
index 0df4866184..987b72aaa2 100644
--- a/src/Avalonia.Themes.Default/ContextMenu.xaml
+++ b/src/Avalonia.Themes.Default/ContextMenu.xaml
@@ -1,4 +1,5 @@
 <Style xmlns="https://github.com/avaloniaui" Selector="ContextMenu">
+    <Setter Property="Background" Value="{DynamicResource ThemeBackgroundBrush}"/>
     <Setter Property="BorderBrush" Value="{DynamicResource ThemeBorderMidBrush}"/>
     <Setter Property="BorderThickness" Value="1"/>
     <Setter Property="Padding" Value="4,2"/>
diff --git a/src/Avalonia.Themes.Default/MenuItem.xaml b/src/Avalonia.Themes.Default/MenuItem.xaml
index 18bf79ce6c..05c286c1f5 100644
--- a/src/Avalonia.Themes.Default/MenuItem.xaml
+++ b/src/Avalonia.Themes.Default/MenuItem.xaml
@@ -62,7 +62,7 @@
                    PlacementMode="Right"
                    IsLightDismissEnabled="False"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
-              <Border Background="{TemplateBinding Background}"
+              <Border Background="{DynamicResource ThemeBackgroundBrush}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">
                 <ScrollViewer Classes="menuscroller">                  
@@ -113,7 +113,7 @@
                    IsLightDismissEnabled="True"
                    OverlayInputPassThroughElement="{Binding $parent[Menu]}"
                    IsOpen="{TemplateBinding IsSubMenuOpen, Mode=TwoWay}">
-              <Border Background="{TemplateBinding Background}"
+              <Border Background="{DynamicResource ThemeBackgroundBrush}"
                       BorderBrush="{DynamicResource ThemeBorderMidBrush}"
                       BorderThickness="{TemplateBinding BorderThickness}">
                 <ScrollViewer Classes="menuscroller">

From 0709bbfe0f2b907363b02ba0fae3279e62120ed6 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Mon, 25 Oct 2021 03:52:11 -0400
Subject: [PATCH 5/7] Fix tests

---
 .../OverlayPopupHost.xaml                     |  5 +-
 .../Primitives/PopupTests.cs                  | 75 +++++++++++++------
 2 files changed, 56 insertions(+), 24 deletions(-)

diff --git a/src/Avalonia.Themes.Default/OverlayPopupHost.xaml b/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
index 5f24388b6e..301e19d208 100644
--- a/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
+++ b/src/Avalonia.Themes.Default/OverlayPopupHost.xaml
@@ -1,13 +1,14 @@
 <Style xmlns="https://github.com/avaloniaui" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Selector="OverlayPopupHost">
-  <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
-  <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}"/>
+  <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}" />
+  <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}" />
   <Setter Property="FontFamily" Value="{x:Static FontFamily.Default}" />
   <Setter Property="FontWeight" Value="400" />
   <Setter Property="FontStyle" Value="Normal" />
   <Setter Property="Template">
     <ControlTemplate>
+      <!--  Do not forget to update Templated_Control_With_Popup_In_Template_Should_Set_TemplatedParent test  -->
       <VisualLayerManager IsPopup="True">
         <ContentPresenter Name="PART_ContentPresenter"
                           Background="{TemplateBinding Background}"
diff --git a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
index 9223b08c81..090a20c857 100644
--- a/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
+++ b/tests/Avalonia.Controls.UnitTests/Primitives/PopupTests.cs
@@ -294,6 +294,7 @@ namespace Avalonia.Controls.UnitTests.Primitives
         [Fact]
         public void Templated_Control_With_Popup_In_Template_Should_Set_TemplatedParent()
         {
+            // Test uses OverlayPopupHost default template
             using (CreateServices())
             {
                 PopupContentControl target;
@@ -316,33 +317,63 @@ namespace Avalonia.Controls.UnitTests.Primitives
                 var children = popupRoot.GetVisualDescendants().ToList();
                 var types = children.Select(x => x.GetType().Name).ToList();
 
-                Assert.Equal(
-                    new[]
-                    {
-                        "Panel",
-                        "Border",
-                        "VisualLayerManager",
-                        "ContentPresenter",
-                        "ContentPresenter",
-                        "Border",
-                    },
-                    types);
+                if (UsePopupHost)
+                {
+                    Assert.Equal(
+                        new[]
+                        {
+                            "VisualLayerManager",
+                            "ContentPresenter",
+                            "ContentPresenter",
+                            "Border",
+                        },
+                        types);
+                }
+                else
+                {
+                    Assert.Equal(
+                        new[]
+                        {
+                            "Panel",
+                            "Border",
+                            "VisualLayerManager",
+                            "ContentPresenter",
+                            "ContentPresenter",
+                            "Border",
+                        },
+                        types);
+                }
 
                 var templatedParents = children
                     .OfType<IControl>()
                     .Select(x => x.TemplatedParent).ToList();
 
-                Assert.Equal(
-                    new object[]
-                    {
-                        popupRoot,
-                        popupRoot,
-                        popupRoot,
-                        popupRoot,
-                        target,
-                        null,
-                    },
-                    templatedParents);
+                if (UsePopupHost)
+                {
+                    Assert.Equal(
+                        new object[]
+                        {
+                            popupRoot,
+                            popupRoot,
+                            target,
+                            null,
+                        },
+                        templatedParents);
+                }
+                else
+                {
+                    Assert.Equal(
+                        new object[]
+                        {
+                            popupRoot,
+                            popupRoot,
+                            popupRoot,
+                            popupRoot,
+                            target,
+                            null,
+                        },
+                        templatedParents);
+                }
             }
         }
 

From 40dd16f9aef4f99ba26bfae10536204719996c86 Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Mon, 25 Oct 2021 16:10:12 -0400
Subject: [PATCH 6/7] Update MenuFlyoutPresenter.cs

---
 src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs b/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
index b1d3df9ddd..3a45c85c70 100644
--- a/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
+++ b/src/Avalonia.Controls/Flyouts/MenuFlyoutPresenter.cs
@@ -8,6 +8,15 @@ namespace Avalonia.Controls
 {
     public class MenuFlyoutPresenter : MenuBase
     {
+        public static readonly StyledProperty<CornerRadius> CornerRadiusProperty =
+            Border.CornerRadiusProperty.AddOwner<FlyoutPresenter>();
+
+        public CornerRadius CornerRadius
+        {
+            get => GetValue(CornerRadiusProperty);
+            set => SetValue(CornerRadiusProperty, value);
+        }
+
         public MenuFlyoutPresenter()
             :base(new DefaultMenuInteractionHandler(true))
         {

From 4dc71e27f8d6cc053b4bcf9839be767ef04be2ae Mon Sep 17 00:00:00 2001
From: Max Katz <maxkatz6@outlook.com>
Date: Tue, 26 Oct 2021 10:36:48 -0400
Subject: [PATCH 7/7] Use {x:Null} instead of transparent for popup root

---
 src/Avalonia.Themes.Default/PopupRoot.xaml         | 2 +-
 src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Themes.Default/PopupRoot.xaml b/src/Avalonia.Themes.Default/PopupRoot.xaml
index 92344fb130..9468cc5535 100644
--- a/src/Avalonia.Themes.Default/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Default/PopupRoot.xaml
@@ -1,7 +1,7 @@
 <Style xmlns="https://github.com/avaloniaui"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Selector="PopupRoot">
-  <Setter Property="Background" Value="Transparent"/>
+  <Setter Property="Background" Value="{x:Null}"/>
   <Setter Property="TransparencyLevelHint" Value="Transparent" />
   <Setter Property="Foreground" Value="{DynamicResource ThemeForegroundBrush}"/>
   <Setter Property="FontSize" Value="{DynamicResource FontSizeNormal}"/>
diff --git a/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml b/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
index 1d9e94260d..1e573913b9 100644
--- a/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/PopupRoot.xaml
@@ -1,7 +1,7 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
   <Style Selector="PopupRoot">
-    <Setter Property="Background" Value="Transparent"/>
+    <Setter Property="Background" Value="{x:Null}"/>
     <Setter Property="TransparencyLevelHint" Value="Transparent" />
     <Setter Property="Foreground" Value="{DynamicResource SystemControlForegroundBaseHighBrush}"/>
     <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}"/>