From ca46e8ab1569d40c54b4468b728919af340960eb Mon Sep 17 00:00:00 2001
From: Sia Gupta <siagupta@microsoft.com>
Date: Tue, 21 Jan 2025 21:24:34 +0530
Subject: [PATCH 1/3] Adding styles for GridSplitter in fluent and also adding
 control brushes for the same

---
 .../Resources/Theme/Dark.xaml                 |  7 ++
 .../Resources/Theme/HC.xaml                   |  7 ++
 .../Resources/Theme/Light.xaml                |  7 ++
 .../Styles/GridSplitter.xaml                  | 69 +++++++++++++++++++
 .../Themes/Fluent.Dark.xaml                   | 48 +++++++++++++
 .../Themes/Fluent.HC.xaml                     | 48 +++++++++++++
 .../Themes/Fluent.Light.xaml                  | 48 +++++++++++++
 7 files changed, 234 insertions(+)
 create mode 100644 src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml

diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Dark.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Dark.xaml
index 305a819d347..a3dbf373546 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Dark.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Dark.xaml
@@ -475,6 +475,13 @@
     <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource AcrylicBackgroundFillColorDefault}" />
     <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SurfaceStrokeColorFlyout}" />
 
+    <!-- GridSplitter -->
+    <SolidColorBrush x:Key="GridsplitterBackground" Color="{StaticResource ControlAltFillColorTransparent}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource ControlAltFillColorTertiary}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource ControlAltFillColorQuarternary}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource ControlAltFillColorDisabled}" />
+    <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource ControlStrongFillColorDefault}" />
+
     <!--  HyperlinkButton  -->
     <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="{StaticResource SubtleFillColorTransparent}" />
     <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SubtleFillColorSecondary}" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/HC.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/HC.xaml
index 56208b9124a..77c45068d71 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/HC.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/HC.xaml
@@ -350,6 +350,13 @@
     <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource SystemColorWindowColor}" />
     <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SystemColorWindowTextColor}" />
 
+    <!-- GridSplitter -->
+    <SolidColorBrush x:Key="GridsplitterBackground" Color="Transparent" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource SystemColorHighlightTextColor}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource SystemColorHighlightColor}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource SystemColorWindowColor}" />
+    <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource SystemColorButtonTextColor}" />
+
     <!--  HyperlinkButton  -->
     <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="Transparent" />
     <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SystemColorWindowColor}" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Light.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Light.xaml
index b205e7d492d..02acffb048b 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Light.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Resources/Theme/Light.xaml
@@ -472,6 +472,13 @@
     <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource AcrylicBackgroundFillColorDefault}" />
     <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SurfaceStrokeColorFlyout}" />
 
+    <!-- GridSplitter -->
+    <SolidColorBrush x:Key="GridsplitterBackground" Color="{StaticResource ControlAltFillColorTransparent}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource ControlAltFillColorTertiary}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource ControlAltFillColorQuarternary}" />
+    <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource ControlAltFillColorDisabled}" />
+    <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource ControlStrongFillColorDefault}" />
+
     <!--  HyperlinkButton  -->
     <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="{StaticResource SubtleFillColorTransparent}" />
     <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SubtleFillColorSecondary}" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
new file mode 100644
index 00000000000..7316f8c61d1
--- /dev/null
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
@@ -0,0 +1,69 @@
+<!--
+    This Source Code Form is subject to the terms of the MIT License.
+    If a copy of the MIT was not distributed with this file, You can obtain one at https://opensource.org/licenses/MIT.
+    Copyright (C) Leszek Pomianowski and WPF UI Contributors.
+    All Rights Reserved.
+    
+    Based on Microsoft XAML for Win UI
+    Copyright (c) Microsoft Corporation. All Rights Reserved.
+-->
+
+<ResourceDictionary 
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:system="clr-namespace:System;assembly=System.Runtime">
+
+    <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
+    <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
+    <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+    <Thickness x:Key="GridsplitterPadding">4</Thickness>
+
+    <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
+        <Setter Property="IsTabStop" Value="True" />
+        <Setter Property="HorizontalAlignment" Value="Stretch" />
+        <Setter Property="VerticalAlignment" Value="Stretch" />
+        <Setter Property="MinHeight" Value="8" />
+        <Setter Property="MinWidth" Value="8" />
+        <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+        <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
+        <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
+        <Setter Property="HorizontalContentAlignment" Value="Center" />
+        <Setter Property="VerticalContentAlignment" Value="Center" />
+        <Setter Property="Template">
+            <Setter.Value>
+                <ControlTemplate TargetType="{x:Type GridSplitter}">
+                    <Border x:Name="RootGrid" 
+                        BorderBrush="{TemplateBinding BorderBrush}"
+                        BorderThickness="{TemplateBinding BorderThickness}"
+                        Background="{TemplateBinding Background}">
+                        <Rectangle x:Name="PART_Thumb"
+                            Width="{StaticResource GridsplitterThumbWidth}"
+                            Height="{StaticResource GridsplitterThumbHeight}"
+                            Margin="{TemplateBinding Padding}"
+                            Fill="{TemplateBinding Foreground}"
+                            RadiusX="{StaticResource GridsplitterThumbRadius}"
+                            RadiusY="{StaticResource GridsplitterThumbRadius}" />
+                    </Border>
+                    <ControlTemplate.Triggers>
+                        <Trigger Property="IsMouseOver" Value="True">
+                                <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPointerOver}" />
+                        </Trigger>
+                        <Trigger Property="IsDragging" Value="True">
+                                <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPressed}" />
+                        </Trigger>
+                        <Trigger Property="IsEnabled"  Value="False">
+                                <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundDisabled}" />
+                                <Setter TargetName="PART_Thumb" Property="Opacity" Value="0.45"/>
+                        </Trigger>
+                        <Trigger Property="ResizeDirection" Value="Rows">
+                                <Setter TargetName="PART_Thumb" Property="Width" Value="{DynamicResource GridsplitterThumbHeight}"/>
+                                <Setter TargetName="PART_Thumb" Property="Height" Value="{DynamicResource GridsplitterThumbWidth}"/>
+                        </Trigger>
+                    </ControlTemplate.Triggers>
+                </ControlTemplate>
+            </Setter.Value>
+        </Setter>
+    </Style>
+
+    <Style BasedOn="{StaticResource DefaultGridSplitterStyle}" TargetType="{x:Type GridSplitter}" />
+</ResourceDictionary>
\ No newline at end of file
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
index 311562a4eb2..d241c4c7356 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
@@ -469,6 +469,12 @@
   <!--  Flyout  -->
   <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource AcrylicBackgroundFillColorDefault}" />
   <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SurfaceStrokeColorFlyout}" />
+  <!-- GridSplitter -->
+  <SolidColorBrush x:Key="GridsplitterBackground" Color="{StaticResource ControlAltFillColorTransparent}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource ControlAltFillColorTertiary}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource ControlAltFillColorQuarternary}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource ControlAltFillColorDisabled}" />
+  <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource ControlStrongFillColorDefault}" />
   <!--  HyperlinkButton  -->
   <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="{StaticResource SubtleFillColorTransparent}" />
   <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SubtleFillColorSecondary}" />
@@ -2652,6 +2658,48 @@
     <Setter Property="Focusable" Value="False" />
     <Setter Property="SnapsToDevicePixels" Value="True" />
   </Style>
+  <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
+  <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
+  <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <Thickness x:Key="GridsplitterPadding">4</Thickness>
+  <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
+    <Setter Property="IsTabStop" Value="True" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="VerticalAlignment" Value="Stretch" />
+    <Setter Property="MinHeight" Value="8" />
+    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
+    <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="Template">
+      <Setter.Value>
+        <ControlTemplate TargetType="{x:Type GridSplitter}">
+          <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
+            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+          </Border>
+          <ControlTemplate.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPointerOver}" />
+            </Trigger>
+            <Trigger Property="IsDragging" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPressed}" />
+            </Trigger>
+            <Trigger Property="IsEnabled" Value="False">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundDisabled}" />
+              <Setter TargetName="PART_Thumb" Property="Opacity" Value="0.45" />
+            </Trigger>
+            <Trigger Property="ResizeDirection" Value="Rows">
+              <Setter TargetName="PART_Thumb" Property="Width" Value="{DynamicResource GridsplitterThumbHeight}" />
+              <Setter TargetName="PART_Thumb" Property="Height" Value="{DynamicResource GridsplitterThumbWidth}" />
+            </Trigger>
+          </ControlTemplate.Triggers>
+        </ControlTemplate>
+      </Setter.Value>
+    </Setter>
+  </Style>
+  <Style BasedOn="{StaticResource DefaultGridSplitterStyle}" TargetType="{x:Type GridSplitter}" />
   <Style x:Key="{x:Type GroupItem}" TargetType="{x:Type GroupItem}">
     <Setter Property="Template">
       <Setter.Value>
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
index 2e6117d68e8..03662fc1e09 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
@@ -367,6 +367,12 @@
   <!--  Flyout  -->
   <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource SystemColorWindowColor}" />
   <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SystemColorWindowTextColor}" />
+  <!-- GridSplitter -->
+  <SolidColorBrush x:Key="GridsplitterBackground" Color="Transparent" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource SystemColorHighlightTextColor}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource SystemColorHighlightColor}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource SystemColorWindowColor}" />
+  <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource SystemColorButtonTextColor}" />
   <!--  HyperlinkButton  -->
   <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="Transparent" />
   <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SystemColorWindowColor}" />
@@ -2633,6 +2639,48 @@
     <Setter Property="Focusable" Value="False" />
     <Setter Property="SnapsToDevicePixels" Value="True" />
   </Style>
+  <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
+  <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
+  <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <Thickness x:Key="GridsplitterPadding">4</Thickness>
+  <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
+    <Setter Property="IsTabStop" Value="True" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="VerticalAlignment" Value="Stretch" />
+    <Setter Property="MinHeight" Value="8" />
+    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
+    <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="Template">
+      <Setter.Value>
+        <ControlTemplate TargetType="{x:Type GridSplitter}">
+          <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
+            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+          </Border>
+          <ControlTemplate.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPointerOver}" />
+            </Trigger>
+            <Trigger Property="IsDragging" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPressed}" />
+            </Trigger>
+            <Trigger Property="IsEnabled" Value="False">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundDisabled}" />
+              <Setter TargetName="PART_Thumb" Property="Opacity" Value="0.45" />
+            </Trigger>
+            <Trigger Property="ResizeDirection" Value="Rows">
+              <Setter TargetName="PART_Thumb" Property="Width" Value="{DynamicResource GridsplitterThumbHeight}" />
+              <Setter TargetName="PART_Thumb" Property="Height" Value="{DynamicResource GridsplitterThumbWidth}" />
+            </Trigger>
+          </ControlTemplate.Triggers>
+        </ControlTemplate>
+      </Setter.Value>
+    </Setter>
+  </Style>
+  <Style BasedOn="{StaticResource DefaultGridSplitterStyle}" TargetType="{x:Type GridSplitter}" />
   <Style x:Key="{x:Type GroupItem}" TargetType="{x:Type GroupItem}">
     <Setter Property="Template">
       <Setter.Value>
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
index 9b00e9ac8bc..3607dbc7f71 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
@@ -466,6 +466,12 @@
   <!--  Flyout  -->
   <SolidColorBrush x:Key="FlyoutBackground" Color="{StaticResource AcrylicBackgroundFillColorDefault}" />
   <SolidColorBrush x:Key="FlyoutBorderBrush" Color="{StaticResource SurfaceStrokeColorFlyout}" />
+  <!-- GridSplitter -->
+  <SolidColorBrush x:Key="GridsplitterBackground" Color="{StaticResource ControlAltFillColorTransparent}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPointerOver" Color="{StaticResource ControlAltFillColorTertiary}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundPressed" Color="{StaticResource ControlAltFillColorQuarternary}" />
+  <SolidColorBrush x:Key="GridsplitterBackgroundDisabled" Color="{StaticResource ControlAltFillColorDisabled}" />
+  <SolidColorBrush x:Key="GridsplitterForeground" Color="{StaticResource ControlStrongFillColorDefault}" />
   <!--  HyperlinkButton  -->
   <SolidColorBrush x:Key="HyperlinkButtonBackground" Color="{StaticResource SubtleFillColorTransparent}" />
   <SolidColorBrush x:Key="HyperlinkButtonBackgroundPointerOver" Color="{StaticResource SubtleFillColorSecondary}" />
@@ -2649,6 +2655,48 @@
     <Setter Property="Focusable" Value="False" />
     <Setter Property="SnapsToDevicePixels" Value="True" />
   </Style>
+  <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
+  <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
+  <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <Thickness x:Key="GridsplitterPadding">4</Thickness>
+  <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
+    <Setter Property="IsTabStop" Value="True" />
+    <Setter Property="HorizontalAlignment" Value="Stretch" />
+    <Setter Property="VerticalAlignment" Value="Stretch" />
+    <Setter Property="MinHeight" Value="8" />
+    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
+    <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
+    <Setter Property="HorizontalContentAlignment" Value="Center" />
+    <Setter Property="VerticalContentAlignment" Value="Center" />
+    <Setter Property="Template">
+      <Setter.Value>
+        <ControlTemplate TargetType="{x:Type GridSplitter}">
+          <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
+            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+          </Border>
+          <ControlTemplate.Triggers>
+            <Trigger Property="IsMouseOver" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPointerOver}" />
+            </Trigger>
+            <Trigger Property="IsDragging" Value="True">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundPressed}" />
+            </Trigger>
+            <Trigger Property="IsEnabled" Value="False">
+              <Setter TargetName="RootGrid" Property="Background" Value="{DynamicResource GridsplitterBackgroundDisabled}" />
+              <Setter TargetName="PART_Thumb" Property="Opacity" Value="0.45" />
+            </Trigger>
+            <Trigger Property="ResizeDirection" Value="Rows">
+              <Setter TargetName="PART_Thumb" Property="Width" Value="{DynamicResource GridsplitterThumbHeight}" />
+              <Setter TargetName="PART_Thumb" Property="Height" Value="{DynamicResource GridsplitterThumbWidth}" />
+            </Trigger>
+          </ControlTemplate.Triggers>
+        </ControlTemplate>
+      </Setter.Value>
+    </Setter>
+  </Style>
+  <Style BasedOn="{StaticResource DefaultGridSplitterStyle}" TargetType="{x:Type GridSplitter}" />
   <Style x:Key="{x:Type GroupItem}" TargetType="{x:Type GroupItem}">
     <Setter Property="Template">
       <Setter.Value>

From fd18ddd8e9c42ee2529e155e623a69cef444ef37 Mon Sep 17 00:00:00 2001
From: Sia Gupta <siagupta@microsoft.com>
Date: Wed, 19 Feb 2025 19:55:25 +0530
Subject: [PATCH 2/3] Addressing PR feedback

---
 .../Styles/GridSplitter.xaml                           | 10 ++++++----
 .../Themes/Fluent.Dark.xaml                            |  8 +++++---
 .../PresentationFramework.Fluent/Themes/Fluent.HC.xaml |  8 +++++---
 .../Themes/Fluent.Light.xaml                           |  8 +++++---
 4 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
index 7316f8c61d1..d418db1afa0 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
@@ -16,14 +16,16 @@
     <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
     <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
     <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+    <system:Double x:Key="GridsplitterMinHeight">8</system:Double>
+    <system:Double x:Key="GridsplitterMinWidth">8</system:Double>
     <Thickness x:Key="GridsplitterPadding">4</Thickness>
 
     <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
         <Setter Property="IsTabStop" Value="True" />
         <Setter Property="HorizontalAlignment" Value="Stretch" />
         <Setter Property="VerticalAlignment" Value="Stretch" />
-        <Setter Property="MinHeight" Value="8" />
-        <Setter Property="MinWidth" Value="8" />
+        <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
+        <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
         <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
         <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
         <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
@@ -37,8 +39,8 @@
                         BorderThickness="{TemplateBinding BorderThickness}"
                         Background="{TemplateBinding Background}">
                         <Rectangle x:Name="PART_Thumb"
-                            Width="{StaticResource GridsplitterThumbWidth}"
-                            Height="{StaticResource GridsplitterThumbHeight}"
+                            Width="{DynamicResource GridsplitterThumbWidth}"
+                            Height="{DynamicResource GridsplitterThumbHeight}"
                             Margin="{TemplateBinding Padding}"
                             Fill="{TemplateBinding Foreground}"
                             RadiusX="{StaticResource GridsplitterThumbRadius}"
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
index d241c4c7356..4cc6776f0bd 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
@@ -2661,13 +2661,15 @@
   <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
   <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
   <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <system:Double x:Key="GridsplitterMinHeight">8</system:Double>
+  <system:Double x:Key="GridsplitterMinWidth">8</system:Double>
   <Thickness x:Key="GridsplitterPadding">4</Thickness>
   <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
     <Setter Property="IsTabStop" Value="True" />
     <Setter Property="HorizontalAlignment" Value="Stretch" />
     <Setter Property="VerticalAlignment" Value="Stretch" />
-    <Setter Property="MinHeight" Value="8" />
-    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
+    <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
@@ -2677,7 +2679,7 @@
       <Setter.Value>
         <ControlTemplate TargetType="{x:Type GridSplitter}">
           <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
-            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+            <Rectangle x:Name="PART_Thumb" Width="{DynamicResource GridsplitterThumbWidth}" Height="{DynamicResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
           </Border>
           <ControlTemplate.Triggers>
             <Trigger Property="IsMouseOver" Value="True">
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
index 03662fc1e09..b09e0d5d00f 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
@@ -2642,13 +2642,15 @@
   <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
   <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
   <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <system:Double x:Key="GridsplitterMinHeight">8</system:Double>
+  <system:Double x:Key="GridsplitterMinWidth">8</system:Double>
   <Thickness x:Key="GridsplitterPadding">4</Thickness>
   <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
     <Setter Property="IsTabStop" Value="True" />
     <Setter Property="HorizontalAlignment" Value="Stretch" />
     <Setter Property="VerticalAlignment" Value="Stretch" />
-    <Setter Property="MinHeight" Value="8" />
-    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
+    <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
@@ -2658,7 +2660,7 @@
       <Setter.Value>
         <ControlTemplate TargetType="{x:Type GridSplitter}">
           <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
-            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+            <Rectangle x:Name="PART_Thumb" Width="{DynamicResource GridsplitterThumbWidth}" Height="{DynamicResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
           </Border>
           <ControlTemplate.Triggers>
             <Trigger Property="IsMouseOver" Value="True">
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
index 3607dbc7f71..95bbd97e938 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
@@ -2658,13 +2658,15 @@
   <system:Double x:Key="GridsplitterThumbHeight">24</system:Double>
   <system:Double x:Key="GridsplitterThumbWidth">4</system:Double>
   <system:Double x:Key="GridsplitterThumbRadius">2</system:Double>
+  <system:Double x:Key="GridsplitterMinHeight">8</system:Double>
+  <system:Double x:Key="GridsplitterMinWidth">8</system:Double>
   <Thickness x:Key="GridsplitterPadding">4</Thickness>
   <Style x:Key="DefaultGridSplitterStyle" TargetType="{x:Type GridSplitter}">
     <Setter Property="IsTabStop" Value="True" />
     <Setter Property="HorizontalAlignment" Value="Stretch" />
     <Setter Property="VerticalAlignment" Value="Stretch" />
-    <Setter Property="MinHeight" Value="8" />
-    <Setter Property="MinWidth" Value="8" />
+    <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
+    <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
@@ -2674,7 +2676,7 @@
       <Setter.Value>
         <ControlTemplate TargetType="{x:Type GridSplitter}">
           <Border x:Name="RootGrid" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}">
-            <Rectangle x:Name="PART_Thumb" Width="{StaticResource GridsplitterThumbWidth}" Height="{StaticResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
+            <Rectangle x:Name="PART_Thumb" Width="{DynamicResource GridsplitterThumbWidth}" Height="{DynamicResource GridsplitterThumbHeight}" Margin="{TemplateBinding Padding}" Fill="{TemplateBinding Foreground}" RadiusX="{StaticResource GridsplitterThumbRadius}" RadiusY="{StaticResource GridsplitterThumbRadius}" />
           </Border>
           <ControlTemplate.Triggers>
             <Trigger Property="IsMouseOver" Value="True">

From b0ab866756bb982a0b63053660b220c1b800adc7 Mon Sep 17 00:00:00 2001
From: Sia Gupta <siagupta@microsoft.com>
Date: Thu, 20 Feb 2025 20:24:44 +0530
Subject: [PATCH 3/3] Addressing PR comments

---
 .../Styles/GridSplitter.xaml                         | 12 +-----------
 .../Themes/Fluent.Dark.xaml                          |  2 +-
 .../Themes/Fluent.HC.xaml                            |  2 +-
 .../Themes/Fluent.Light.xaml                         |  2 +-
 .../PresentationFramework.Fluent/Themes/Fluent.xaml  |  1 +
 5 files changed, 5 insertions(+), 14 deletions(-)

diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
index d418db1afa0..e948431dd3f 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Styles/GridSplitter.xaml
@@ -1,13 +1,3 @@
-<!--
-    This Source Code Form is subject to the terms of the MIT License.
-    If a copy of the MIT was not distributed with this file, You can obtain one at https://opensource.org/licenses/MIT.
-    Copyright (C) Leszek Pomianowski and WPF UI Contributors.
-    All Rights Reserved.
-    
-    Based on Microsoft XAML for Win UI
-    Copyright (c) Microsoft Corporation. All Rights Reserved.
--->
-
 <ResourceDictionary 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
@@ -26,7 +16,7 @@
         <Setter Property="VerticalAlignment" Value="Stretch" />
         <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
         <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
-        <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+        <Setter Property="Padding" Value="{DynamicResource GridsplitterPadding}" />
         <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
         <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
         <Setter Property="HorizontalContentAlignment" Value="Center" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
index 4cc6776f0bd..343f97f9ae9 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Dark.xaml
@@ -2670,7 +2670,7 @@
     <Setter Property="VerticalAlignment" Value="Stretch" />
     <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
-    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
     <Setter Property="HorizontalContentAlignment" Value="Center" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
index b09e0d5d00f..ad585f9bf63 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.HC.xaml
@@ -2651,7 +2651,7 @@
     <Setter Property="VerticalAlignment" Value="Stretch" />
     <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
-    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
     <Setter Property="HorizontalContentAlignment" Value="Center" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
index 95bbd97e938..5b32635b3ea 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.Light.xaml
@@ -2667,7 +2667,7 @@
     <Setter Property="VerticalAlignment" Value="Stretch" />
     <Setter Property="MinHeight" Value="{DynamicResource GridsplitterMinHeight}" />
     <Setter Property="MinWidth" Value="{DynamicResource GridsplitterMinHeight}" />
-    <Setter Property="Padding" Value="{StaticResource GridsplitterPadding}" />
+    <Setter Property="Padding" Value="{DynamicResource GridsplitterPadding}" />
     <Setter Property="Foreground" Value="{DynamicResource GridsplitterForeground}" />
     <Setter Property="Background" Value="{DynamicResource GridsplitterBackground}" />
     <Setter Property="HorizontalContentAlignment" Value="Center" />
diff --git a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.xaml b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.xaml
index 901ee89318f..5f8fc9c38ff 100644
--- a/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.xaml
+++ b/src/Microsoft.DotNet.Wpf/src/Themes/PresentationFramework.Fluent/Themes/Fluent.xaml
@@ -22,6 +22,7 @@
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/DatePicker.xaml" />
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/Expander.xaml" />
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/Frame.xaml" />
+        <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/GridSplitter.xaml" />
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/GroupItem.xaml" />
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/HeaderedContentControl.xaml" />
         <ResourceDictionary Source="pack://application:,,,/PresentationFramework.Fluent;component/Styles/Label.xaml" />