From f57f8673fbaedc76c78653167376aeb8773933ee Mon Sep 17 00:00:00 2001
From: Luke Blevins <lukeblevins15@outlook.com>
Date: Sun, 21 Mar 2021 17:36:50 -0400
Subject: [PATCH 1/5] Move horizontal TabView out of PaneHolderPage

---
 Files/App.xaml.cs                  |  2 --
 Files/Views/MainPage.xaml          | 32 ++++++++++++++++++++++++++++-
 Files/Views/MainPage.xaml.cs       | 33 +++++++++++++++++++++++++++++-
 Files/Views/PaneHolderPage.xaml    | 16 +--------------
 Files/Views/PaneHolderPage.xaml.cs | 14 -------------
 5 files changed, 64 insertions(+), 33 deletions(-)

diff --git a/Files/App.xaml.cs b/Files/App.xaml.cs
index 0990f8dbba17..b24b1470681b 100644
--- a/Files/App.xaml.cs
+++ b/Files/App.xaml.cs
@@ -44,9 +44,7 @@ sealed partial class App : Application
 
         public static SemaphoreSlim SemaphoreSlim = new SemaphoreSlim(1, 1);
         public static StorageHistoryWrapper HistoryWrapper = new StorageHistoryWrapper();
-
         public static IBundlesSettings BundlesSettings = new BundlesSettingsViewModel();
-
         public static SettingsViewModel AppSettings { get; private set; }
         public static InteractionViewModel InteractionViewModel { get; private set; }
         public static JumpListManager JumpList { get; } = new JumpListManager();
diff --git a/Files/Views/MainPage.xaml b/Files/Views/MainPage.xaml
index 5b494f5e51d5..745319d44bac 100644
--- a/Files/Views/MainPage.xaml
+++ b/Files/Views/MainPage.xaml
@@ -13,6 +13,9 @@
     KeyboardAcceleratorPlacementMode="Hidden"
     NavigationCacheMode="Required"
     mc:Ignorable="d">
+    <Page.Resources>
+        <converters:WidthToRightMargin x:Key="WidthToRightMarginConverter" />
+    </Page.Resources>
     <Page.KeyboardAccelerators>
         <KeyboardAccelerator
             Key="Number1"
@@ -73,6 +76,33 @@
     </Page.KeyboardAccelerators>
 
     <Grid TabFocusNavigation="Cycle">
-        <ContentPresenter Content="{x:Bind SelectedTabItem.Control, Mode=OneWay}" />
+        <Grid.ColumnDefinitions>
+            <ColumnDefinition
+                x:Name="SidebarColumn"
+                Width="{x:Bind AppSettings.SidebarWidth, Mode=OneWay}"
+                MinWidth="200"
+                MaxWidth="500" />
+            <ColumnDefinition Width="*" />
+        </Grid.ColumnDefinitions>
+        <Grid
+            x:Name="DragArea"
+            Margin="38,0,0,0"
+            Grid.ColumnSpan="2"
+            Canvas.ZIndex="3"
+            Height="40"
+            VerticalAlignment="Top"
+            HorizontalAlignment="Stretch"
+            Background="Transparent"
+            Loaded="DragArea_Loaded" />
+        <Grid Padding="2,0,0,0" Margin="{x:Bind DragRegionWidth, Mode=OneWay, Converter={StaticResource WidthToRightMarginConverter}}"
+            Canvas.ZIndex="4" VerticalAlignment="Top" Grid.Column="1">
+            <usercontrols:HorizontalMultitaskingControl
+                    x:Name="horizontalMultitaskingControl"
+                    x:FieldModifier="public"
+                    Height="50"
+                    x:Load="{x:Bind converters:MultiBooleanConverter.OrConvert(AppSettings.IsHorizontalTabStripOn, local1:App.InteractionViewModel.IsHorizontalTabStripVisible), Mode=OneWay}"
+                    Loaded="HorizontalMultitaskingControl_Loaded" />
+        </Grid>
+        <ContentPresenter Grid.ColumnSpan="2" Content="{x:Bind SelectedTabItem.Control, Mode=OneWay}" />
     </Grid>
 </Page>
\ No newline at end of file
diff --git a/Files/Views/MainPage.xaml.cs b/Files/Views/MainPage.xaml.cs
index c2befbf48cdb..6571265a90f3 100644
--- a/Files/Views/MainPage.xaml.cs
+++ b/Files/Views/MainPage.xaml.cs
@@ -33,6 +33,19 @@ namespace Files.Views
     public sealed partial class MainPage : Page, INotifyPropertyChanged
     {
         public SettingsViewModel AppSettings => App.AppSettings;
+        private double dragReigonWidth;
+        public double DragRegionWidth
+        {
+            get => dragReigonWidth;
+            set
+            {
+                if (value != dragReigonWidth)
+                {
+                    dragReigonWidth = value;
+                    NotifyPropertyChanged("DragRegionWidth");
+                }
+            }
+        }
         public static IMultitaskingControl MultitaskingControl { get; set; }
 
         private TabItem selectedTabItem;
@@ -62,7 +75,7 @@ public MainPage()
             ApplicationView.PreferredLaunchWindowingMode = ApplicationViewWindowingMode.Auto;
             var CoreTitleBar = CoreApplication.GetCurrentView().TitleBar;
             CoreTitleBar.ExtendViewIntoTitleBar = true;
-
+            CoreTitleBar.LayoutMetricsChanged += TitleBar_LayoutMetricsChanged;
             var flowDirectionSetting = ResourceContext.GetForCurrentView().QualifierValues["LayoutDirection"];
 
             if (flowDirectionSetting == "RTL")
@@ -72,6 +85,24 @@ public MainPage()
             AllowDrop = true;
         }
 
+        private void TitleBar_LayoutMetricsChanged(CoreApplicationViewTitleBar sender, object args)
+        {
+            DragRegionWidth = sender.SystemOverlayRightInset;
+        }
+
+        private void DragArea_Loaded(object sender, RoutedEventArgs e)
+        {
+            Window.Current.SetTitleBar(sender as Grid);
+        }
+
+        private void HorizontalMultitaskingControl_Loaded(object sender, RoutedEventArgs e)
+        {
+            if (!(MultitaskingControl is HorizontalMultitaskingControl))
+            {
+                MultitaskingControl = horizontalMultitaskingControl;
+            }
+        }
+
         protected override async void OnNavigatedTo(NavigationEventArgs eventArgs)
         {
             if (eventArgs.NavigationMode != NavigationMode.Back)
diff --git a/Files/Views/PaneHolderPage.xaml b/Files/Views/PaneHolderPage.xaml
index c4f78ccce7f6..b2a44ad29580 100644
--- a/Files/Views/PaneHolderPage.xaml
+++ b/Files/Views/PaneHolderPage.xaml
@@ -34,8 +34,6 @@
                 </ResourceDictionary>
             </ResourceDictionary.ThemeDictionaries>
 
-            <converters:WidthToRightMargin x:Key="WidthToRightMarginConverter" />
-
             <Style x:Key="DefaultGridSplitterStyle" TargetType="Custom:GridSplitter">
                 <Setter Property="IsTabStop" Value="True" />
                 <Setter Property="UseSystemFocusVisuals" Value="True" />
@@ -135,19 +133,7 @@
                     <RowDefinition Height="Auto" MinHeight="50" />
                     <RowDefinition Height="*" />
                 </Grid.RowDefinitions>
-                <Grid
-                    x:Name="DragArea"
-                    Grid.ColumnSpan="2"
-                    HorizontalAlignment="Stretch"
-                    Background="Transparent"
-                    Loaded="DragArea_Loaded" />
-
-                <multitaskingcontrol:HorizontalMultitaskingControl
-                    x:Name="horizontalMultitaskingControl"
-                    Margin="{x:Bind DragRegionWidth, Converter={StaticResource WidthToRightMarginConverter}}"
-                    x:FieldModifier="public"
-                    x:Load="{x:Bind converters:MultiBooleanConverter.OrConvert(AppSettings.IsHorizontalTabStripOn, local1:App.InteractionViewModel.IsHorizontalTabStripVisible), Mode=OneWay}"
-                    Loaded="HorizontalMultitaskingControl_Loaded" />
+                
 
                 <Border x:Name="PaneLeftLoader" Grid.Row="1">
                     <local:ModernShellPage
diff --git a/Files/Views/PaneHolderPage.xaml.cs b/Files/Views/PaneHolderPage.xaml.cs
index a5ad93b7544d..debccbe5c760 100644
--- a/Files/Views/PaneHolderPage.xaml.cs
+++ b/Files/Views/PaneHolderPage.xaml.cs
@@ -30,7 +30,6 @@ namespace Files.Views
     public sealed partial class PaneHolderPage : Page, IPaneHolder, ITabItemContent, INotifyPropertyChanged
     {
         public SettingsViewModel AppSettings => App.AppSettings;
-        public double DragRegionWidth => CoreApplication.GetCurrentView().TitleBar.SystemOverlayRightInset;
         public IFilesystemHelpers FilesystemHelpers => ActivePane?.FilesystemHelpers;
 
         private readonly GridLength CompactSidebarWidth;
@@ -80,11 +79,6 @@ private void AppSettings_PropertyChanged(object sender, PropertyChangedEventArgs
             }
         }
 
-        private void DragArea_Loaded(object sender, RoutedEventArgs e)
-        {
-            Window.Current.SetTitleBar(sender as Grid);
-        }
-
         private void Current_SizeChanged(object sender, WindowSizeChangedEventArgs e)
         {
             if ((Window.Current.Content as Frame).CurrentSourcePageType != typeof(Settings))
@@ -592,14 +586,6 @@ private void SidebarControl_SidebarItemInvoked(object sender, SidebarItemInvoked
 
             ActivePane?.NavigateToPath(navigationPath, sourcePageType);
         }
-
-        private void HorizontalMultitaskingControl_Loaded(object sender, RoutedEventArgs e)
-        {
-            if (!(MainPage.MultitaskingControl is HorizontalMultitaskingControl))
-            {
-                MainPage.MultitaskingControl = horizontalMultitaskingControl;
-            }
-        }
     }
 
     public class PaneNavigationArguments

From 9d9647788b70278fe6d786419e079a814cc554bd Mon Sep 17 00:00:00 2001
From: Luke Blevins <lukeblevins15@outlook.com>
Date: Sun, 21 Mar 2021 18:14:22 -0400
Subject: [PATCH 2/5] Add back removed tab item transitions

---
 .../HorizontalMultitaskingControl.xaml                    | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Files/UserControls/MultitaskingControl/HorizontalMultitaskingControl.xaml b/Files/UserControls/MultitaskingControl/HorizontalMultitaskingControl.xaml
index 661698753694..500b026453b2 100644
--- a/Files/UserControls/MultitaskingControl/HorizontalMultitaskingControl.xaml
+++ b/Files/UserControls/MultitaskingControl/HorizontalMultitaskingControl.xaml
@@ -2,9 +2,6 @@
     x:Class="Files.UserControls.MultitaskingControl.HorizontalMultitaskingControl"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:Windows10version1903="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract, 8)"
-    xmlns:controls="using:Microsoft.Toolkit.Uwp.UI.Controls"
-    xmlns:converters="using:Files.Converters"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:local="using:Files.UserControls.MultitaskingControl"
     xmlns:local1="using:Files"
@@ -182,7 +179,9 @@
                             <Setter.Value>
                                 <TransitionCollection>
                                     <AddDeleteThemeTransition />
+                                    <ContentThemeTransition />
                                     <ReorderThemeTransition />
+                                    <EntranceThemeTransition IsStaggeringEnabled="False" />
                                 </TransitionCollection>
                             </Setter.Value>
                         </Setter>
@@ -360,7 +359,7 @@
                     </Style>
 
                     <Style x:Key="UndockedTabViewItemStyle" TargetType="muxc:TabViewItem">
-                        <Setter Property="HorizontalContentAlignment" Value="Left" />
+                        <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                         <Setter Property="UseSystemFocusVisuals" Value="{StaticResource UseSystemFocusVisuals}" />
                         <Setter Property="Template">
                             <Setter.Value>
@@ -819,6 +818,7 @@
                         ContextFlyout="{StaticResource TabFlyout}"
                         CornerRadius="4"
                         Height="36"
+                        HorizontalAlignment="Stretch"
                         DragEnter="TabViewItem_DragEnter"
                         DragLeave="TabViewItem_DragLeave"
                         Drop="TabViewItem_Drop"

From f48647c67368710259fd44d824d66d0171e889af Mon Sep 17 00:00:00 2001
From: Luke Blevins <lukeblevins15@outlook.com>
Date: Tue, 23 Mar 2021 18:46:43 -0400
Subject: [PATCH 3/5] Fix bug by creating new shared viewmodel for sidebar
 adaptive behavior

---
 Files/Files.csproj                           |   1 +
 Files/UserControls/SidebarControl.xaml.cs    |  12 ++
 Files/ViewModels/AdaptiveSidebarViewModel.cs | 124 ++++++++++++++++++
 Files/Views/MainPage.xaml                    |   4 +-
 Files/Views/MainPage.xaml.cs                 |   1 +
 Files/Views/PaneHolderPage.xaml              |  10 +-
 Files/Views/PaneHolderPage.xaml.cs           | 129 ++++---------------
 7 files changed, 168 insertions(+), 113 deletions(-)
 create mode 100644 Files/ViewModels/AdaptiveSidebarViewModel.cs

diff --git a/Files/Files.csproj b/Files/Files.csproj
index 1812a87887aa..96ff776231f9 100644
--- a/Files/Files.csproj
+++ b/Files/Files.csproj
@@ -284,6 +284,7 @@
     <Compile Include="UserControls\Widgets\Bundles.xaml.cs">
       <DependentUpon>Bundles.xaml</DependentUpon>
     </Compile>
+    <Compile Include="ViewModels\AdaptiveSidebarViewModel.cs" />
     <Compile Include="ViewModels\BaseJsonSettingsViewModel.cs" />
     <Compile Include="ViewModels\Bundles\BundleContainerViewModel.cs" />
     <Compile Include="ViewModels\Bundles\BundleItemViewModel.cs" />
diff --git a/Files/UserControls/SidebarControl.xaml.cs b/Files/UserControls/SidebarControl.xaml.cs
index e03e943987d6..7ba6e8b783ef 100644
--- a/Files/UserControls/SidebarControl.xaml.cs
+++ b/Files/UserControls/SidebarControl.xaml.cs
@@ -212,6 +212,18 @@ public void UnpinItem_Click(object sender, RoutedEventArgs e)
             }
         }
 
+        public static GridLength GetSidebarCompactSize()
+        {
+            if (App.Current.Resources.TryGetValue("NavigationViewCompactPaneLength", out object paneLength))
+            {
+                if (paneLength is double paneLengthDouble)
+                {
+                    return new GridLength(paneLengthDouble);
+                }
+            }
+            return new GridLength(200);
+        }
+
         private void Sidebar_ItemInvoked(Microsoft.UI.Xaml.Controls.NavigationView sender, Microsoft.UI.Xaml.Controls.NavigationViewItemInvokedEventArgs args)
         {
             if (args.InvokedItem == null || args.InvokedItemContainer == null)
diff --git a/Files/ViewModels/AdaptiveSidebarViewModel.cs b/Files/ViewModels/AdaptiveSidebarViewModel.cs
new file mode 100644
index 000000000000..8cb503852219
--- /dev/null
+++ b/Files/ViewModels/AdaptiveSidebarViewModel.cs
@@ -0,0 +1,124 @@
+using Files.UserControls;
+using Files.Views;
+using Microsoft.Toolkit.Mvvm.ComponentModel;
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using System.Text;
+using System.Threading.Tasks;
+using Windows.UI.Core;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+
+namespace Files.ViewModels
+{
+    public class AdaptiveSidebarViewModel : ObservableObject, IDisposable
+    {
+        public static readonly GridLength CompactSidebarWidth = SidebarControl.GetSidebarCompactSize();
+        public event EventHandler<WindowCompactStateChangedEventArgs> WindowCompactStateChanged;
+        private bool isWindowCompactSize;
+
+        public bool IsWindowCompactSize
+        {
+            get => isWindowCompactSize;
+            set
+            {
+                if (isWindowCompactSize != value)
+                {
+                    isWindowCompactSize = value;
+                    WindowCompactStateChanged?.Invoke(this, new WindowCompactStateChangedEventArgs(isWindowCompactSize));
+                    
+                    OnPropertyChanged(nameof(IsWindowCompactSize));
+                    OnPropertyChanged(nameof(SidebarWidth));
+                    OnPropertyChanged(nameof(IsSidebarOpen));
+                }
+            }
+        }
+
+        public GridLength SidebarWidth
+        {
+            get => IsWindowCompactSize || !IsSidebarOpen ? CompactSidebarWidth : App.AppSettings.SidebarWidth;
+            set
+            {
+                if (IsWindowCompactSize || !IsSidebarOpen)
+                {
+                    return;
+                }
+                if (App.AppSettings.SidebarWidth != value)
+                {
+                    App.AppSettings.SidebarWidth = value;
+                    OnPropertyChanged(nameof(SidebarWidth));
+                }
+            }
+        }
+
+        public bool IsSidebarOpen
+        {
+            get => !IsWindowCompactSize && App.AppSettings.IsSidebarOpen;
+            set
+            {
+                if (IsWindowCompactSize)
+                {
+                    return;
+                }
+                if (App.AppSettings.IsSidebarOpen != value)
+                {
+                    App.AppSettings.IsSidebarOpen = value;
+                    OnPropertyChanged(nameof(SidebarWidth));
+                    OnPropertyChanged(nameof(IsSidebarOpen));
+                }
+            }
+        }
+
+        public AdaptiveSidebarViewModel()
+        {
+            Window.Current.SizeChanged += Current_SizeChanged;
+            App.AppSettings.PropertyChanged += AppSettings_PropertyChanged;
+            Current_SizeChanged(null, null);
+        }
+
+        private void AppSettings_PropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(App.AppSettings.SidebarWidth):
+                    OnPropertyChanged(nameof(SidebarWidth));
+                    break;
+
+                case nameof(App.AppSettings.IsSidebarOpen):
+                    if (App.AppSettings.IsSidebarOpen != IsSidebarOpen)
+                    {
+                        OnPropertyChanged(nameof(IsSidebarOpen));
+                    }
+                    break;
+            }
+        }
+
+        private void Current_SizeChanged(object sender, WindowSizeChangedEventArgs e)
+        {
+            if ((Window.Current.Content as Frame).CurrentSourcePageType != typeof(Settings))
+            {
+                IsWindowCompactSize = Window.Current.Bounds.Width <= 750;
+            }
+        }
+
+
+        public void Dispose()
+        {
+            Window.Current.SizeChanged -= Current_SizeChanged;
+            App.AppSettings.PropertyChanged -= AppSettings_PropertyChanged;
+        }
+    }
+
+    public class WindowCompactStateChangedEventArgs
+    {
+        public bool IsWindowCompact { get; set; }
+
+        public WindowCompactStateChangedEventArgs(bool isCompact)
+        {
+            IsWindowCompact = isCompact;
+        }
+    }
+}
diff --git a/Files/Views/MainPage.xaml b/Files/Views/MainPage.xaml
index 745319d44bac..c9ee5be6ae19 100644
--- a/Files/Views/MainPage.xaml
+++ b/Files/Views/MainPage.xaml
@@ -79,9 +79,7 @@
         <Grid.ColumnDefinitions>
             <ColumnDefinition
                 x:Name="SidebarColumn"
-                Width="{x:Bind AppSettings.SidebarWidth, Mode=OneWay}"
-                MinWidth="200"
-                MaxWidth="500" />
+                Width="{x:Bind SidebarAdaptiveViewModel.SidebarWidth, Mode=OneWay}" />
             <ColumnDefinition Width="*" />
         </Grid.ColumnDefinitions>
         <Grid
diff --git a/Files/Views/MainPage.xaml.cs b/Files/Views/MainPage.xaml.cs
index 6571265a90f3..c4f1dfabd695 100644
--- a/Files/Views/MainPage.xaml.cs
+++ b/Files/Views/MainPage.xaml.cs
@@ -67,6 +67,7 @@ public TabItem SelectedTabItem
         public static ObservableCollection<TabItem> AppInstances = new ObservableCollection<TabItem>();
         public static BulkConcurrentObservableCollection<INavigationControlItem> SideBarItems = new BulkConcurrentObservableCollection<INavigationControlItem>();
         public static SemaphoreSlim SideBarItemsSemaphore = new SemaphoreSlim(1, 1);
+        public AdaptiveSidebarViewModel SidebarAdaptiveViewModel = new AdaptiveSidebarViewModel();
 
         public MainPage()
         {
diff --git a/Files/Views/PaneHolderPage.xaml b/Files/Views/PaneHolderPage.xaml
index b2a44ad29580..1c2cd4b90bb5 100644
--- a/Files/Views/PaneHolderPage.xaml
+++ b/Files/Views/PaneHolderPage.xaml
@@ -91,7 +91,7 @@
         <Grid.ColumnDefinitions>
             <ColumnDefinition
                 x:Name="SidebarColumn"
-                Width="{x:Bind SidebarWidth, Mode=TwoWay}"
+                Width="{x:Bind adaptiveSidebarViewModel.SidebarWidth, Mode=TwoWay}"
                 MinWidth="200"
                 MaxWidth="500" />
             <ColumnDefinition Width="*" />
@@ -100,8 +100,8 @@
         <controls:SidebarControl
             x:Name="SidebarControl"
             Grid.RowSpan="2"
-            IsOpen="{x:Bind IsSidebarOpen, Mode=TwoWay}"
-            IsCompact="{x:Bind IsWindowCompactSize, Mode=OneWay}"
+            IsOpen="{x:Bind adaptiveSidebarViewModel.IsSidebarOpen, Mode=TwoWay}"
+            IsCompact="{x:Bind adaptiveSidebarViewModel.IsWindowCompactSize, Mode=OneWay}"
             CanOpenInNewPane="{x:Bind IsMultiPaneEnabled, Mode=OneWay}"
             EmptyRecycleBinCommand="{x:Bind EmptyRecycleBinCommand, Mode=OneWay}"
             Loaded="SidebarControl_Loaded" />
@@ -287,7 +287,7 @@
             ResizeBehavior="BasedOnAlignment"
             ResizeDirection="Auto"
             Style="{StaticResource DefaultGridSplitterStyle}"
-            Visibility="{x:Bind IsSidebarOpen, Mode=OneWay}">
+            Visibility="{x:Bind adaptiveSidebarViewModel.IsSidebarOpen, Mode=OneWay}">
             <Custom:GridSplitter.RenderTransform>
                 <TranslateTransform X="0" />
             </Custom:GridSplitter.RenderTransform>
@@ -297,7 +297,7 @@
             <VisualStateGroup>
                 <VisualState>
                     <VisualState.StateTriggers>
-                        <StateTrigger IsActive="{x:Bind IsSidebarOpen, Mode=OneWay, Converter={StaticResource BoolNegationConverter}}" />
+                        <StateTrigger IsActive="{x:Bind adaptiveSidebarViewModel.IsSidebarOpen, Mode=OneWay, Converter={StaticResource BoolNegationConverter}}" />
                     </VisualState.StateTriggers>
                     <VisualState.Setters>
                         <Setter Target="SidebarColumn.MinWidth" Value="{ThemeResource NavigationViewCompactPaneLength}"/>
diff --git a/Files/Views/PaneHolderPage.xaml.cs b/Files/Views/PaneHolderPage.xaml.cs
index debccbe5c760..8a8b05d4594d 100644
--- a/Files/Views/PaneHolderPage.xaml.cs
+++ b/Files/Views/PaneHolderPage.xaml.cs
@@ -31,130 +31,40 @@ public sealed partial class PaneHolderPage : Page, IPaneHolder, ITabItemContent,
     {
         public SettingsViewModel AppSettings => App.AppSettings;
         public IFilesystemHelpers FilesystemHelpers => ActivePane?.FilesystemHelpers;
-
-        private readonly GridLength CompactSidebarWidth;
-
         public ICommand EmptyRecycleBinCommand { get; private set; }
+        private AdaptiveSidebarViewModel adaptiveSidebarViewModel => ((Window.Current.Content as Frame).Content as MainPage).SidebarAdaptiveViewModel;
 
         public PaneHolderPage()
         {
             this.InitializeComponent();
-            this.Loaded += PaneHolderPage_Loaded;
-            AppSettings.PropertyChanged += AppSettings_PropertyChanged;
-            Window.Current.SizeChanged += Current_SizeChanged;
 
             this.ActivePane = PaneLeft;
             this.IsRightPaneVisible = IsMultiPaneEnabled && AppSettings.AlwaysOpenDualPaneInNewTab;
-
-            if (App.Current.Resources.TryGetValue("NavigationViewCompactPaneLength", out object paneLength))
-            {
-                if (paneLength is double paneLengthDouble)
-                {
-                    this.CompactSidebarWidth = new GridLength(paneLengthDouble);
-                }
-            }
+            App.AppSettings.PropertyChanged += AppSettings_PropertyChanged;
+            adaptiveSidebarViewModel.WindowCompactStateChanged += AdaptiveSidebarViewModel_WindowCompactStateChanged;
             // TODO: fallback / error when failed to get NavigationViewCompactPaneLength value?
         }
 
-        private void PaneHolderPage_Loaded(object sender, RoutedEventArgs e)
+        private void AdaptiveSidebarViewModel_WindowCompactStateChanged(object sender, WindowCompactStateChangedEventArgs e)
         {
-            Current_SizeChanged(null, null);
-        }
-
-        private void AppSettings_PropertyChanged(object sender, PropertyChangedEventArgs e)
-        {
-            switch (e.PropertyName)
+            if (e.IsWindowCompact)
             {
-                case nameof(AppSettings.IsDualPaneEnabled):
-                    NotifyPropertyChanged(nameof(IsMultiPaneEnabled));
-                    break;
-
-                case nameof(AppSettings.SidebarWidth):
-                    NotifyPropertyChanged(nameof(SidebarWidth));
-                    break;
-
-                case nameof(AppSettings.IsSidebarOpen):
-                    NotifyPropertyChanged(nameof(IsSidebarOpen));
-                    break;
+                wasRightPaneVisible = isRightPaneVisible;
+                IsRightPaneVisible = false;
             }
-        }
-
-        private void Current_SizeChanged(object sender, WindowSizeChangedEventArgs e)
-        {
-            if ((Window.Current.Content as Frame).CurrentSourcePageType != typeof(Settings))
+            else if (wasRightPaneVisible)
             {
-                IsWindowCompactSize = Window.Current.Bounds.Width <= 750;
+                IsRightPaneVisible = true;
+                wasRightPaneVisible = false;
             }
+            NotifyPropertyChanged(nameof(IsMultiPaneEnabled));
         }
 
         private bool wasRightPaneVisible;
 
-        private bool isWindowCompactSize;
-
-        public bool IsWindowCompactSize
-        {
-            get => isWindowCompactSize;
-            set
-            {
-                if (isWindowCompactSize != value)
-                {
-                    isWindowCompactSize = value;
-                    if (isWindowCompactSize)
-                    {
-                        wasRightPaneVisible = isRightPaneVisible;
-                        IsRightPaneVisible = false;
-                    }
-                    else if (wasRightPaneVisible)
-                    {
-                        IsRightPaneVisible = true;
-                        wasRightPaneVisible = false;
-                    }
-                    NotifyPropertyChanged(nameof(IsWindowCompactSize));
-                    NotifyPropertyChanged(nameof(IsMultiPaneEnabled));
-                    NotifyPropertyChanged(nameof(SidebarWidth));
-                    NotifyPropertyChanged(nameof(IsSidebarOpen));
-                }
-            }
-        }
-
-        public GridLength SidebarWidth
-        {
-            get => IsWindowCompactSize || !IsSidebarOpen ? CompactSidebarWidth : AppSettings.SidebarWidth;
-            set
-            {
-                if (IsWindowCompactSize || !IsSidebarOpen)
-                {
-                    return;
-                }
-                if (AppSettings.SidebarWidth != value)
-                {
-                    AppSettings.SidebarWidth = value;
-                    NotifyPropertyChanged(nameof(SidebarWidth));
-                }
-            }
-        }
-
-        public bool IsSidebarOpen
-        {
-            get => !IsWindowCompactSize && AppSettings.IsSidebarOpen;
-            set
-            {
-                if (IsWindowCompactSize)
-                {
-                    return;
-                }
-                if (AppSettings.IsSidebarOpen != value)
-                {
-                    AppSettings.IsSidebarOpen = value;
-                    NotifyPropertyChanged(nameof(SidebarWidth));
-                    NotifyPropertyChanged(nameof(IsSidebarOpen));
-                }
-            }
-        }
-
         public bool IsMultiPaneEnabled
         {
-            get => AppSettings.IsDualPaneEnabled && !IsWindowCompactSize;
+            get => AppSettings.IsDualPaneEnabled && !adaptiveSidebarViewModel.IsWindowCompactSize;
         }
 
         private string navParamsLeft;
@@ -285,13 +195,22 @@ protected override void OnNavigatedTo(NavigationEventArgs eventArgs)
             }
         }
 
+        private void AppSettings_PropertyChanged(object sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(App.AppSettings.IsDualPaneEnabled):
+                    NotifyPropertyChanged(nameof(IsMultiPaneEnabled));
+                    break;
+            }
+        }
+
         public void Dispose()
         {
-            this.Loaded -= PaneHolderPage_Loaded;
+            App.AppSettings.PropertyChanged -= AppSettings_PropertyChanged;
+            adaptiveSidebarViewModel.WindowCompactStateChanged -= AdaptiveSidebarViewModel_WindowCompactStateChanged;
             PaneLeft?.Dispose();
             PaneRight?.Dispose();
-            Window.Current.SizeChanged -= Current_SizeChanged;
-            AppSettings.PropertyChanged -= AppSettings_PropertyChanged;
             if (SidebarControl != null)
             {
                 SidebarControl.SidebarItemInvoked -= SidebarControl_SidebarItemInvoked;

From c62fa08384fc1def1b5a792eb2c050940bc90ab8 Mon Sep 17 00:00:00 2001
From: Luke Blevins <lukeblevins15@outlook.com>
Date: Tue, 23 Mar 2021 19:46:36 -0400
Subject: [PATCH 4/5] Prevent crashing with multiple tabs

---
 .../Converters/NavigationViewCompactConverter.cs |  2 +-
 Files/UserControls/SidebarControl.xaml.cs        | 16 ++++++++++++++--
 Files/ViewModels/AdaptiveSidebarViewModel.cs     |  5 ++++-
 3 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/Files/Converters/NavigationViewCompactConverter.cs b/Files/Converters/NavigationViewCompactConverter.cs
index d8d1cba500dc..c37b989b805d 100644
--- a/Files/Converters/NavigationViewCompactConverter.cs
+++ b/Files/Converters/NavigationViewCompactConverter.cs
@@ -13,7 +13,7 @@ public object Convert(object value, Type targetType, object parameter, string la
 
         public object ConvertBack(object value, Type targetType, object parameter, string language)
         {
-            throw new NotImplementedException();
+            return (value as NavigationViewPaneDisplayMode?) == NavigationViewPaneDisplayMode.LeftCompact;
         }
     }
 }
\ No newline at end of file
diff --git a/Files/UserControls/SidebarControl.xaml.cs b/Files/UserControls/SidebarControl.xaml.cs
index 7ba6e8b783ef..4b3c4804c964 100644
--- a/Files/UserControls/SidebarControl.xaml.cs
+++ b/Files/UserControls/SidebarControl.xaml.cs
@@ -51,7 +51,13 @@ public sealed partial class SidebarControl : UserControl, INotifyPropertyChanged
         public bool IsOpen
         {
             get => (bool)GetValue(IsOpenProperty);
-            set => SetValue(IsOpenProperty, value);
+            set 
+            {
+                if (this.IsLoaded)
+                {
+                    SetValue(IsOpenProperty, value);
+                }
+            }
         }
 
         public static readonly DependencyProperty IsCompactProperty = DependencyProperty.Register(nameof(IsCompact), typeof(bool), typeof(SidebarControl), new PropertyMetadata(false));
@@ -59,7 +65,13 @@ public bool IsOpen
         public bool IsCompact
         {
             get => (bool)GetValue(IsCompactProperty);
-            set => SetValue(IsCompactProperty, value);
+            set 
+            { 
+                if(this.IsLoaded)
+                {
+                    SetValue(IsCompactProperty, value);
+                }
+            }
         }
 
         public static readonly DependencyProperty EmptyRecycleBinCommandProperty = DependencyProperty.Register(nameof(EmptyRecycleBinCommand), typeof(ICommand), typeof(SidebarControl), new PropertyMetadata(null));
diff --git a/Files/ViewModels/AdaptiveSidebarViewModel.cs b/Files/ViewModels/AdaptiveSidebarViewModel.cs
index 8cb503852219..ba69338ebaec 100644
--- a/Files/ViewModels/AdaptiveSidebarViewModel.cs
+++ b/Files/ViewModels/AdaptiveSidebarViewModel.cs
@@ -100,7 +100,10 @@ private void Current_SizeChanged(object sender, WindowSizeChangedEventArgs e)
         {
             if ((Window.Current.Content as Frame).CurrentSourcePageType != typeof(Settings))
             {
-                IsWindowCompactSize = Window.Current.Bounds.Width <= 750;
+                if (IsWindowCompactSize != Window.Current.Bounds.Width <= 750)
+                {
+                    IsWindowCompactSize = Window.Current.Bounds.Width <= 750;
+                }
             }
         }
 

From 6d5ec1bdd19215758d301f4ef39deb0ff91bbe11 Mon Sep 17 00:00:00 2001
From: Luke Blevins <lukeblevins15@outlook.com>
Date: Tue, 23 Mar 2021 20:17:25 -0400
Subject: [PATCH 5/5] Set inset right margin directly

---
 Files/Views/MainPage.xaml    | 12 +++++++++---
 Files/Views/MainPage.xaml.cs | 33 ++++++++-------------------------
 2 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/Files/Views/MainPage.xaml b/Files/Views/MainPage.xaml
index 944dd23ccfb6..2d9458c33eb1 100644
--- a/Files/Views/MainPage.xaml
+++ b/Files/Views/MainPage.xaml
@@ -5,11 +5,17 @@
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:i="using:Microsoft.Xaml.Interactivity"
-    xmlns:icore="using:Microsoft.Xaml.Interactions.Core"
+    xmlns:icore="using:Microsoft.Xaml.Interactions.Core" 
+    xmlns:converters="using:Files.Converters" 
+    xmlns:usercontrols="using:Files.UserControls.MultitaskingControl" 
+    xmlns:local1="using:Files" xmlns:viewmodels="using:Files.ViewModels"
     Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"
     KeyboardAcceleratorPlacementMode="Hidden"
     NavigationCacheMode="Required"
     mc:Ignorable="d">
+    <Page.DataContext>
+        <viewmodels:MainPageViewModel/>
+    </Page.DataContext>
     <Page.Resources>
         <converters:WidthToRightMargin x:Key="WidthToRightMarginConverter" />
     </Page.Resources>
@@ -159,7 +165,7 @@
             HorizontalAlignment="Stretch"
             Background="Transparent"
             Loaded="DragArea_Loaded" />
-        <Grid Padding="2,0,0,0" Margin="{x:Bind DragRegionWidth, Mode=OneWay, Converter={StaticResource WidthToRightMarginConverter}}"
+        <Grid x:Name="RightMarginGrid" Padding="2,0,0,0"
             Canvas.ZIndex="4" VerticalAlignment="Top" Grid.Column="1">
             <usercontrols:HorizontalMultitaskingControl
                     x:Name="horizontalMultitaskingControl"
@@ -168,6 +174,6 @@
                     x:Load="{x:Bind converters:MultiBooleanConverter.OrConvert(AppSettings.IsHorizontalTabStripOn, local1:App.InteractionViewModel.IsHorizontalTabStripVisible), Mode=OneWay}"
                     Loaded="HorizontalMultitaskingControl_Loaded" />
         </Grid>
-        <ContentPresenter Grid.ColumnSpan="2" Content="{x:Bind ViewModel.SelectedTabItem.Control, Mode=OneWay}" />
+        <ContentPresenter Grid.ColumnSpan="2" Content="{x:Bind ((viewmodels:MainPageViewModel)DataContext).SelectedTabItem.Control, Mode=OneWay}" />
     </Grid>
 </Page>
\ No newline at end of file
diff --git a/Files/Views/MainPage.xaml.cs b/Files/Views/MainPage.xaml.cs
index 0ac36865f670..81031d3ede23 100644
--- a/Files/Views/MainPage.xaml.cs
+++ b/Files/Views/MainPage.xaml.cs
@@ -1,4 +1,5 @@
-using Files.ViewModels;
+using Files.UserControls.MultitaskingControl;
+using Files.ViewModels;
 using Windows.ApplicationModel.Core;
 using Windows.ApplicationModel.Resources.Core;
 using Windows.UI.ViewManagement;
@@ -14,36 +15,18 @@ namespace Files.Views
     public sealed partial class MainPage : Page
     {
         public SettingsViewModel AppSettings => App.AppSettings;
-        private double dragReigonWidth;
-        public double DragRegionWidth
-        {
-            get => dragReigonWidth;
-            set
-            {
-                if (value != dragReigonWidth)
-                {
-                    dragReigonWidth = value;
-                    NotifyPropertyChanged("DragRegionWidth");
-                }
-            }
-        }
-        public static IMultitaskingControl MultitaskingControl { get; set; }
-
-        private TabItem selectedTabItem;
 
-        public TabItem SelectedTabItem
         public MainPageViewModel ViewModel
         {
             get => (MainPageViewModel)DataContext;
             set => DataContext = value;
         }
+
         public AdaptiveSidebarViewModel SidebarAdaptiveViewModel = new AdaptiveSidebarViewModel();
         public MainPage()
         {
             this.InitializeComponent();
 
-            this.ViewModel = new MainPageViewModel();
-
             ApplicationView.PreferredLaunchWindowingMode = ApplicationViewWindowingMode.Auto;
             var CoreTitleBar = CoreApplication.GetCurrentView().TitleBar;
             CoreTitleBar.ExtendViewIntoTitleBar = true;
@@ -57,11 +40,9 @@ public MainPage()
             AllowDrop = true;
         }
 
-        }
-
         private void TitleBar_LayoutMetricsChanged(CoreApplicationViewTitleBar sender, object args)
         {
-            DragRegionWidth = sender.SystemOverlayRightInset;
+            RightMarginGrid.Margin = new Thickness(0, 0, sender.SystemOverlayRightInset, 0);
         }
 
         private void DragArea_Loaded(object sender, RoutedEventArgs e)
@@ -71,11 +52,13 @@ private void DragArea_Loaded(object sender, RoutedEventArgs e)
 
         private void HorizontalMultitaskingControl_Loaded(object sender, RoutedEventArgs e)
         {
-            if (!(MultitaskingControl is HorizontalMultitaskingControl))
+            if (!(MainPageViewModel.MultitaskingControl is HorizontalMultitaskingControl))
             {
-                MultitaskingControl = horizontalMultitaskingControl;
+                MainPageViewModel.MultitaskingControl = horizontalMultitaskingControl;
             }
         }
+
+        protected override void OnNavigatedTo(NavigationEventArgs e)
         {
             ViewModel.OnNavigatedTo(e);
         }