From baa7c9da69b232b13386bfb414ff537a744f4a81 Mon Sep 17 00:00:00 2001
From: Benedikt Schroeder <benedikt.schroeder@outlook.de>
Date: Thu, 11 Apr 2019 17:49:56 +0200
Subject: [PATCH 1/2] Makes ScrollBar Thumb stylable

---
 src/Avalonia.Themes.Default/ScrollBar.xaml | 34 +++++++++++++++-------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index 2cb8ce2d24..edd678ed56 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -31,11 +31,18 @@
                                               Focusable="False"/>
                             </Track.IncreaseButton>
                             <Thumb Name="thumb">
-                                <Thumb.Template>
-                                    <ControlTemplate>
-                                        <Border Background="{DynamicResource ThemeControlHighBrush}" />
-                                    </ControlTemplate>
-                                </Thumb.Template>
+                                <Thumb.Styles>
+                                    <Style Selector="Thumb">
+                                        <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
+                                        <Setter Property="Template">
+                                            <Setter.Value>
+                                                <ControlTemplate>
+                                                    <Border Background="{TemplateBinding Background}"/>
+                                                </ControlTemplate>
+                                            </Setter.Value>
+                                        </Setter>
+                                    </Style>
+                                </Thumb.Styles>
                             </Thumb>
                         </Track>
                         <RepeatButton Name="PART_LineDownButton"
@@ -85,11 +92,18 @@
                                               Focusable="False"/>
                             </Track.IncreaseButton>
                             <Thumb Name="thumb">
-                                <Thumb.Template>
-                                    <ControlTemplate>
-                                        <Border Background="{DynamicResource ThemeControlHighBrush}" />
-                                    </ControlTemplate>
-                                </Thumb.Template>
+                                <Thumb.Styles>
+                                    <Style Selector="Thumb">
+                                        <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
+                                        <Setter Property="Template">
+                                            <Setter.Value>
+                                                <ControlTemplate>
+                                                    <Border Background="{TemplateBinding Background}"/>
+                                                </ControlTemplate>
+                                            </Setter.Value>
+                                        </Setter>
+                                    </Style>
+                                </Thumb.Styles>
                             </Thumb>
                         </Track>
                         <RepeatButton Name="PART_LineDownButton"

From 55e64e4c744b6836c26cc4409561b3930c441632 Mon Sep 17 00:00:00 2001
From: Benedikt Schroeder <benedikt.schroeder@outlook.de>
Date: Fri, 12 Apr 2019 11:32:59 +0200
Subject: [PATCH 2/2] Move Thumb style outside the control template

---
 src/Avalonia.Themes.Default/ScrollBar.xaml | 40 +++++++---------------
 1 file changed, 12 insertions(+), 28 deletions(-)

diff --git a/src/Avalonia.Themes.Default/ScrollBar.xaml b/src/Avalonia.Themes.Default/ScrollBar.xaml
index edd678ed56..ca308b33c3 100644
--- a/src/Avalonia.Themes.Default/ScrollBar.xaml
+++ b/src/Avalonia.Themes.Default/ScrollBar.xaml
@@ -30,20 +30,7 @@
                                               Classes="repeattrack"
                                               Focusable="False"/>
                             </Track.IncreaseButton>
-                            <Thumb Name="thumb">
-                                <Thumb.Styles>
-                                    <Style Selector="Thumb">
-                                        <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
-                                        <Setter Property="Template">
-                                            <Setter.Value>
-                                                <ControlTemplate>
-                                                    <Border Background="{TemplateBinding Background}"/>
-                                                </ControlTemplate>
-                                            </Setter.Value>
-                                        </Setter>
-                                    </Style>
-                                </Thumb.Styles>
-                            </Thumb>
+                            <Thumb Name="thumb"/>
                         </Track>
                         <RepeatButton Name="PART_LineDownButton"
                                       Classes="repeat"
@@ -91,20 +78,7 @@
                                               Classes="repeattrack"
                                               Focusable="False"/>
                             </Track.IncreaseButton>
-                            <Thumb Name="thumb">
-                                <Thumb.Styles>
-                                    <Style Selector="Thumb">
-                                        <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
-                                        <Setter Property="Template">
-                                            <Setter.Value>
-                                                <ControlTemplate>
-                                                    <Border Background="{TemplateBinding Background}"/>
-                                                </ControlTemplate>
-                                            </Setter.Value>
-                                        </Setter>
-                                    </Style>
-                                </Thumb.Styles>
-                            </Thumb>
+                            <Thumb Name="thumb"/>
                         </Track>
                         <RepeatButton Name="PART_LineDownButton"
                                       Classes="repeat"
@@ -120,6 +94,16 @@
             </ControlTemplate>
         </Setter>
     </Style>
+    <Style Selector="ScrollBar /template/ Thumb#thumb">
+        <Setter Property="Background" Value="{DynamicResource ThemeControlHighBrush}"/>
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate>
+                    <Border Background="{TemplateBinding Background}"/>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
     <Style Selector="ScrollBar:horizontal /template/ Thumb#thumb">
         <Setter Property="MinWidth" Value="{DynamicResource ScrollBarThickness}" />
     </Style>