From 829c4986bf39a4042aaacd50c62bd5230f248cc4 Mon Sep 17 00:00:00 2001
From: Bastian Schmidt <batzen@gmx.org>
Date: Sat, 15 Aug 2020 15:30:09 +0200
Subject: [PATCH] Fixes #840 by fixing logical tree issues

---
 Changelog.md                                  |  1 +
 Fluent.Ribbon/Controls/Ribbon.cs              | 22 +++++--------------
 .../RibbonGroupsContainerScrollViewer.cs      | 17 ++++++++++++++
 Fluent.Ribbon/Controls/RibbonScrollViewer.cs  |  2 +-
 Fluent.Ribbon/Controls/RibbonTabItem.cs       |  2 +-
 Fluent.Ribbon/Themes/Common.xaml              |  2 ++
 .../Themes/Controls/RibbonScrollViewer.xaml   | 16 ++++++++++++--
 7 files changed, 42 insertions(+), 20 deletions(-)
 create mode 100644 Fluent.Ribbon/Controls/RibbonGroupsContainerScrollViewer.cs

diff --git a/Changelog.md b/Changelog.md
index df1979099..2cd4d7694 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -7,6 +7,7 @@
   - [#821](../../issues/821) - Different visual of menu item and submenu item
   - [#830](../../issues/830) - When a window is set to automatically resize to its content, when its title is set in code, it disappears
   - [#834](../../issues/834) - InRibbonGallery resizing issue when changing `Visibility`
+  - [#840](../../issues/840) - Ribbon does not scroll anymore
 
 ## 8.0.0
 
diff --git a/Fluent.Ribbon/Controls/Ribbon.cs b/Fluent.Ribbon/Controls/Ribbon.cs
index ca53bc6f1..17165e6f7 100644
--- a/Fluent.Ribbon/Controls/Ribbon.cs
+++ b/Fluent.Ribbon/Controls/Ribbon.cs
@@ -491,10 +491,10 @@ private static void OnContextMenuOpened(object sender, RoutedEventArgs e)
         private ObservableCollection<Key> keyTipKeys;
 
         // Collection of contextual tab groups
-        private ItemCollectionWithLogicalTreeSupport<RibbonContextualTabGroup> contextualGroups;
+        private ObservableCollection<RibbonContextualTabGroup> contextualGroups;
 
         // Collection of tabs
-        private ItemCollectionWithLogicalTreeSupport<RibbonTabItem> tabs;
+        private ObservableCollection<RibbonTabItem> tabs;
 
         // Collection of toolbar items
         private ObservableCollection<UIElement> toolBarItems;
@@ -824,13 +824,13 @@ public double QuickAccessToolBarHeight
         /// Gets collection of contextual tab groups
         /// </summary>
         [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
-        public ItemCollectionWithLogicalTreeSupport<RibbonContextualTabGroup> ContextualGroups
+        public ObservableCollection<RibbonContextualTabGroup> ContextualGroups
         {
             get
             {
                 if (this.contextualGroups == null)
                 {
-                    this.contextualGroups = new ItemCollectionWithLogicalTreeSupport<RibbonContextualTabGroup>(this);
+                    this.contextualGroups = new ObservableCollection<RibbonContextualTabGroup>();
                 }
 
                 return this.contextualGroups;
@@ -841,13 +841,13 @@ public ItemCollectionWithLogicalTreeSupport<RibbonContextualTabGroup> Contextual
         /// gets collection of ribbon tabs
         /// </summary>
         [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
-        public ItemCollectionWithLogicalTreeSupport<RibbonTabItem> Tabs
+        public ObservableCollection<RibbonTabItem> Tabs
         {
             get
             {
                 if (this.tabs == null)
                 {
-                    this.tabs = new ItemCollectionWithLogicalTreeSupport<RibbonTabItem>(this);
+                    this.tabs = new ObservableCollection<RibbonTabItem>();
                 }
 
                 return this.tabs;
@@ -1906,16 +1906,6 @@ protected override IEnumerator LogicalChildren
                     yield return this.TabControl.ToolbarPanel;
                 }
 
-                foreach (var item in this.Tabs.GetLogicalChildren())
-                {
-                    yield return item;
-                }
-
-                foreach (var item in this.ContextualGroups.GetLogicalChildren())
-                {
-                    yield return item;
-                }
-
                 if (this.layoutRoot != null)
                 {
                     yield return this.layoutRoot;
diff --git a/Fluent.Ribbon/Controls/RibbonGroupsContainerScrollViewer.cs b/Fluent.Ribbon/Controls/RibbonGroupsContainerScrollViewer.cs
new file mode 100644
index 000000000..1d2508192
--- /dev/null
+++ b/Fluent.Ribbon/Controls/RibbonGroupsContainerScrollViewer.cs
@@ -0,0 +1,17 @@
+// ReSharper disable once CheckNamespace
+namespace Fluent
+{
+    using System.Windows;
+    using System.Windows.Controls;
+
+    /// <summary>
+    /// Represents a <see cref="ScrollViewer"/> specific to <see cref="RibbonGroupsContainer"/>.
+    /// </summary>
+    public class RibbonGroupsContainerScrollViewer : ScrollViewer
+    {
+        static RibbonGroupsContainerScrollViewer()
+        {
+            DefaultStyleKeyProperty.OverrideMetadata(typeof(RibbonGroupsContainerScrollViewer), new FrameworkPropertyMetadata(typeof(RibbonGroupsContainerScrollViewer)));
+        }
+    }
+}
\ No newline at end of file
diff --git a/Fluent.Ribbon/Controls/RibbonScrollViewer.cs b/Fluent.Ribbon/Controls/RibbonScrollViewer.cs
index b99c5688f..85724f265 100644
--- a/Fluent.Ribbon/Controls/RibbonScrollViewer.cs
+++ b/Fluent.Ribbon/Controls/RibbonScrollViewer.cs
@@ -5,7 +5,7 @@ namespace Fluent
     using System.Windows.Media;
 
     /// <summary>
-    /// Represents ScrollViewer with modified hit test
+    /// Represents <see cref="ScrollViewer"/> with modified hit test
     /// </summary>
     public class RibbonScrollViewer : ScrollViewer
     {
diff --git a/Fluent.Ribbon/Controls/RibbonTabItem.cs b/Fluent.Ribbon/Controls/RibbonTabItem.cs
index 0461cf50b..c57d984fa 100644
--- a/Fluent.Ribbon/Controls/RibbonTabItem.cs
+++ b/Fluent.Ribbon/Controls/RibbonTabItem.cs
@@ -108,7 +108,7 @@ public string KeyTip
         /// <summary>
         /// Gets ribbon groups container
         /// </summary>
-        public ScrollViewer GroupsContainer { get; } = new ScrollViewer { VerticalScrollBarVisibility = ScrollBarVisibility.Disabled };
+        public ScrollViewer GroupsContainer { get; } = new RibbonGroupsContainerScrollViewer { VerticalScrollBarVisibility = ScrollBarVisibility.Disabled };
 
         /// <summary>
         /// Gets or sets whether ribbon is minimized
diff --git a/Fluent.Ribbon/Themes/Common.xaml b/Fluent.Ribbon/Themes/Common.xaml
index cff316124..6470038e1 100644
--- a/Fluent.Ribbon/Themes/Common.xaml
+++ b/Fluent.Ribbon/Themes/Common.xaml
@@ -45,4 +45,6 @@
     <Style TargetType="{x:Type Fluent:RibbonTitleBar}" BasedOn="{StaticResource RibbonTitleBarStyle}" />
     <Style TargetType="{x:Type Fluent:RibbonTabControl}" BasedOn="{StaticResource RibbonTabControlStyle}" />
     <Style TargetType="{x:Type Fluent:QuickAccessToolBar}" BasedOn="{StaticResource QuickAccessToolbarStyle}" />
+    
+    <Style TargetType="{x:Type Fluent:RibbonGroupsContainerScrollViewer}" BasedOn="{StaticResource Fluent.Ribbon.Styles.RibbonGroupsContainerScrollViewer}" />
 </ResourceDictionary>
\ No newline at end of file
diff --git a/Fluent.Ribbon/Themes/Controls/RibbonScrollViewer.xaml b/Fluent.Ribbon/Themes/Controls/RibbonScrollViewer.xaml
index 03a36cea5..1f5b0389d 100644
--- a/Fluent.Ribbon/Themes/Controls/RibbonScrollViewer.xaml
+++ b/Fluent.Ribbon/Themes/Controls/RibbonScrollViewer.xaml
@@ -343,6 +343,15 @@
 
     <Style x:Key="ScrollViewerStyle"
            TargetType="{x:Type ScrollViewer}">
+        <Style.Resources>
+            <Style x:Key="{x:Type ScrollBar}"
+                   TargetType="{x:Type ScrollBar}"
+                   BasedOn="{StaticResource ScrollBarWhite}" />
+        </Style.Resources>
+
+        <Setter Property="Template"
+                Value="{DynamicResource ScrollViewerControlTemplate}" />
+
         <Style.Triggers>
             <Trigger Property="IsEnabled"
                      Value="false">
@@ -350,8 +359,11 @@
                         Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" />
             </Trigger>
         </Style.Triggers>
-        <Setter Property="Template"
-                Value="{DynamicResource ScrollViewerControlTemplate}" />
+    </Style>
+
+    <Style x:Key="Fluent.Ribbon.Styles.RibbonGroupsContainerScrollViewer"
+           TargetType="{x:Type Fluent:RibbonGroupsContainerScrollViewer}"
+           BasedOn="{StaticResource RibbonScrollViewer}">
     </Style>
 
     <ControlTemplate x:Key="ScrollViewerControlTemplate"