From a536aa97b4091a304f6e6223ca2fa028005339b2 Mon Sep 17 00:00:00 2001
From: Dong Bin <14807942+rabbitism@users.noreply.github.com>
Date: Fri, 23 Jan 2026 20:03:39 +0800
Subject: [PATCH] Disable scroll chaining for ScrollVIewers in popup. (#20503)

* feat: disable scroll chaining for AutoCompleteBox, ComboBox, and MenuScrollViewer.

* feat: disable scroll chaining for AutoCompleteBox, ComboBox, and MenuFlyoutPresenter

* feat: enable scroll chaining for ScrollViewer in MenuFlyoutPresenter.
---
 src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml  | 3 ++-
 src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml         | 1 +
 src/Avalonia.Themes.Fluent/Controls/MenuScrollViewer.xaml | 1 +
 src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml  | 1 +
 src/Avalonia.Themes.Simple/Controls/ComboBox.xaml         | 3 ++-
 src/Avalonia.Themes.Simple/Controls/ScrollViewer.xaml     | 1 +
 6 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml b/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
index 3196d262a1..462dfe0323 100644
--- a/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/AutoCompleteBox.xaml
@@ -66,7 +66,8 @@
                          BorderThickness="0"
                          Background="Transparent"
                          ItemTemplate="{TemplateBinding ItemTemplate}"
-                         Margin="{DynamicResource AutoCompleteListPadding}" />
+                         Margin="{DynamicResource AutoCompleteListPadding}"
+                         ScrollViewer.IsScrollChainingEnabled="False" />
               </Border>
             </Popup>
           </Grid>
diff --git a/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml b/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
index 255cf29133..bcba646461 100644
--- a/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/ComboBox.xaml
@@ -172,6 +172,7 @@
                       HorizontalAlignment="Stretch"
                       CornerRadius="{DynamicResource OverlayCornerRadius}">
                 <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
+                              IsScrollChainingEnabled="False"
                               VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
                               IsDeferredScrollingEnabled="{TemplateBinding (ScrollViewer.IsDeferredScrollingEnabled)}">
                   <ItemsPresenter Name="PART_ItemsPresenter"
diff --git a/src/Avalonia.Themes.Fluent/Controls/MenuScrollViewer.xaml b/src/Avalonia.Themes.Fluent/Controls/MenuScrollViewer.xaml
index 9dd65b1349..8badfa98eb 100644
--- a/src/Avalonia.Themes.Fluent/Controls/MenuScrollViewer.xaml
+++ b/src/Avalonia.Themes.Fluent/Controls/MenuScrollViewer.xaml
@@ -21,6 +21,7 @@
 
   <ControlTheme x:Key="FluentMenuScrollViewer" TargetType="ScrollViewer">
     <Setter Property="Background" Value="Transparent" />
+    <Setter Property="IsScrollChainingEnabled" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
         <DockPanel>
diff --git a/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml b/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
index 10b48a12f6..5b760ba14e 100644
--- a/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/AutoCompleteBox.xaml
@@ -38,6 +38,7 @@
                        BorderThickness="0"
                        Foreground="{TemplateBinding Foreground}"
                        ItemTemplate="{TemplateBinding ItemTemplate}"
+                       ScrollViewer.IsScrollChainingEnabled="False"
                        ScrollViewer.HorizontalScrollBarVisibility="Auto"
                        ScrollViewer.VerticalScrollBarVisibility="Auto" />
             </Border>
diff --git a/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml b/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
index 54e75db0a2..5a6266af6e 100644
--- a/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/ComboBox.xaml
@@ -87,7 +87,8 @@
                       BorderThickness="1">
                 <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
                               VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
-                              IsDeferredScrollingEnabled="{TemplateBinding (ScrollViewer.IsDeferredScrollingEnabled)}">
+                              IsDeferredScrollingEnabled="{TemplateBinding (ScrollViewer.IsDeferredScrollingEnabled)}"
+                              ScrollViewer.IsScrollChainingEnabled="False">
                   <ItemsPresenter Name="PART_ItemsPresenter"
                                   ItemsPanel="{TemplateBinding ItemsPanel}" />
                 </ScrollViewer>
diff --git a/src/Avalonia.Themes.Simple/Controls/ScrollViewer.xaml b/src/Avalonia.Themes.Simple/Controls/ScrollViewer.xaml
index ea62f757c5..f691ff6651 100644
--- a/src/Avalonia.Themes.Simple/Controls/ScrollViewer.xaml
+++ b/src/Avalonia.Themes.Simple/Controls/ScrollViewer.xaml
@@ -40,6 +40,7 @@
   <ControlTheme x:Key="SimpleMenuScrollViewer"
                 TargetType="ScrollViewer">
     <Setter Property="Background" Value="Transparent" />
+    <Setter Property="IsScrollChainingEnabled" Value="False" />
     <Setter Property="Template">
       <ControlTemplate>
         <DockPanel>