Basic work to add AvalonDock using MVVM, avoiding too big changes to existing architecture for now

ILSpy/Analyzers/AnalyzeCommand.cs

@@ -58,17 +58,17 @@ namespace ICSharpCode.ILSpy.Analyzers
 		{
 			if (context.SelectedTreeNodes != null) {
 				foreach (IMemberTreeNode node in context.SelectedTreeNodes) {
-					AnalyzerTreeView.Instance.Analyze(node.Member);
+					MainWindow.Instance.AnalyzerTreeView.Analyze(node.Member);
 				}
 			} else if (context.Reference != null && context.Reference.Reference is IEntity entity) {
-				AnalyzerTreeView.Instance.Analyze(entity);
+				MainWindow.Instance.AnalyzerTreeView.Analyze(entity);
 			}
 		}
 
 		public override bool CanExecute(object parameter)
 		{
-			if (AnalyzerTreeView.Instance.IsKeyboardFocusWithin) {
-				return AnalyzerTreeView.Instance.SelectedItems.OfType<object>().All(n => n is IMemberTreeNode);
+			if (MainWindow.Instance.AnalyzerTreeView.IsKeyboardFocusWithin) {
+				return MainWindow.Instance.AnalyzerTreeView.SelectedItems.OfType<object>().All(n => n is IMemberTreeNode);
 			} else {
 				return MainWindow.Instance.SelectedNodes.All(n => n is IMemberTreeNode);
 			}
@@ -76,13 +76,13 @@ namespace ICSharpCode.ILSpy.Analyzers
 
 		public override void Execute(object parameter)
 		{
-			if (AnalyzerTreeView.Instance.IsKeyboardFocusWithin) {
-				foreach (IMemberTreeNode node in AnalyzerTreeView.Instance.SelectedItems.OfType<IMemberTreeNode>().ToArray()) {
-					AnalyzerTreeView.Instance.Analyze(node.Member);
+			if (MainWindow.Instance.AnalyzerTreeView.IsKeyboardFocusWithin) {
+				foreach (IMemberTreeNode node in MainWindow.Instance.AnalyzerTreeView.SelectedItems.OfType<IMemberTreeNode>().ToArray()) {
+					MainWindow.Instance.AnalyzerTreeView.Analyze(node.Member);
 				}
 			} else {
 				foreach (IMemberTreeNode node in MainWindow.Instance.SelectedNodes) {
-					AnalyzerTreeView.Instance.Analyze(node.Member);
+					MainWindow.Instance.AnalyzerTreeView.Analyze(node.Member);
 				}
 			}
 		}

ILSpy/Analyzers/AnalyzerTreeView.cs

@@ -23,6 +23,8 @@ using System.Linq;
 using System.Windows;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.ILSpy.Analyzers.TreeNodes;
+using ICSharpCode.ILSpy.Docking;
+using ICSharpCode.ILSpy.ViewModels;
 using ICSharpCode.TreeView;
 
 namespace ICSharpCode.ILSpy.Analyzers
@@ -32,21 +34,7 @@ namespace ICSharpCode.ILSpy.Analyzers
 	/// </summary>
 	public class AnalyzerTreeView : SharpTreeView, IPane
 	{
-		static AnalyzerTreeView instance;
-
-		public static AnalyzerTreeView Instance
-		{
-			get
-			{
-				if (instance == null) {
-					App.Current.VerifyAccess();
-					instance = new AnalyzerTreeView();
-				}
-				return instance;
-			}
-		}
-
-		private AnalyzerTreeView()
+		public AnalyzerTreeView()
 		{
 			this.ShowRoot = false;
 			this.Root = new AnalyzerRootNode { Language = MainWindow.Instance.CurrentLanguage };
@@ -72,8 +60,7 @@ namespace ICSharpCode.ILSpy.Analyzers
 
 		public void Show()
 		{
-			if (!IsVisible)
-				MainWindow.Instance.ShowInNewPane("Analyzer", this, PanePosition.Bottom);
+			DockWorkspace.Instance.ToolPanes.Add(AnalyzerPaneModel.Instance);
 		}
 
 		public void Show(AnalyzerTreeNode node)

ILSpy/Commands/DecompileInNewViewCommand.cs

@@ -17,6 +17,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System.Linq;
+using ICSharpCode.ILSpy.Docking;
 using ICSharpCode.ILSpy.Properties;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
@@ -45,7 +46,9 @@ namespace ICSharpCode.ILSpy.Commands
 			var dtv = new DecompilerTextView();
 			var nodes = context.SelectedTreeNodes.Cast<ILSpyTreeNode>().ToArray();
 			var title = string.Join(", ", nodes.Select(x => x.ToString()));
-			MainWindow.Instance.ShowInNewPane(title, dtv, PanePosition.Document);
+			// TODO
+			//MainWindow.Instance.ShowInNewPane(title, dtv, PanePosition.Document);
+			//DockWorkspace.Instance.Documents.Add(new ViewModels.DocumentModel() { Title = title });
 			await dtv.DecompileAsync(MainWindow.Instance.CurrentLanguage, nodes, new DecompilationOptions());
 		}
 	}

ILSpy/Commands/ShowDebugSteps.cs

@@ -1,6 +1,8 @@
 #if DEBUG
 
+using ICSharpCode.ILSpy.Docking;
 using ICSharpCode.ILSpy.Properties;
+using ICSharpCode.ILSpy.ViewModels;
 
 namespace ICSharpCode.ILSpy.Commands
 {
@@ -9,7 +11,7 @@ namespace ICSharpCode.ILSpy.Commands
 	{
 		public override void Execute(object parameter)
 		{
-			DebugSteps.Show();
+			DockWorkspace.Instance.ToolPanes.Add(DebugStepsPaneModel.Instance);
 		}
 	}
 }

ILSpy/DebugSteps.xaml.cs

@@ -4,6 +4,8 @@ using System.Windows.Controls;
 using System.Windows.Input;
 using ICSharpCode.Decompiler.IL;
 using ICSharpCode.Decompiler.IL.Transforms;
+using ICSharpCode.ILSpy.Docking;
+using ICSharpCode.ILSpy.ViewModels;
 
 namespace ICSharpCode.ILSpy
 {
@@ -20,7 +22,7 @@ namespace ICSharpCode.ILSpy
 		ILAstLanguage language;
 #endif
 
-		DebugSteps()
+		public DebugSteps()
 		{
 			InitializeComponent();
 
@@ -79,7 +81,7 @@ namespace ICSharpCode.ILSpy
 
 		public static void Show()
 		{
-			MainWindow.Instance.ShowInNewPane(Properties.Resources.DebugSteps, new DebugSteps(), PanePosition.Top);
+			DockWorkspace.Instance.ToolPanes.Add(DebugStepsPaneModel.Instance);
 		}
 
 		void IPane.Closed()

ILSpy/Docking/ActiveDocumentConverter.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Windows.Data;
+using ICSharpCode.ILSpy.ViewModels;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class ActiveDocumentConverter : IValueConverter
+	{
+		public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
+		{
+			if (value is DocumentModel)
+				return value;
+
+			return Binding.DoNothing;
+		}
+
+		public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
+		{
+			if (value is DocumentModel)
+				return value;
+
+			return Binding.DoNothing;
+		}
+	}
+}

ILSpy/Docking/DockLayoutSettings.cs

@@ -32,7 +32,7 @@ namespace ICSharpCode.ILSpy.Docking
 		public void Deserialize(XmlLayoutSerializer serializer)
 		{
 			if (!Valid)
-				return;
+				rawSettings = "<LayoutRoot />";
 
 			using (StringReader reader = new StringReader(rawSettings)) {
 				serializer.Deserialize(reader);

ILSpy/Docking/DockWorkspace.cs

@@ -0,0 +1,47 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using ICSharpCode.ILSpy.ViewModels;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class DockWorkspace : INotifyPropertyChanged
+	{
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		public static DockWorkspace Instance { get; } = new DockWorkspace();
+
+		private DockWorkspace()
+		{
+			Documents.Add(new DocumentModel());
+			ToolPanes.Add(AssemblyListPaneModel.Instance);
+		}
+
+		public PaneCollection<DocumentModel> Documents { get; } = new PaneCollection<DocumentModel>();
+
+		public PaneCollection<ToolPaneModel> ToolPanes { get; } = new PaneCollection<ToolPaneModel>();
+
+		public void Remove(PaneModel model)
+		{
+			Documents.Remove(model as DocumentModel);
+			ToolPanes.Remove(model as ToolPaneModel);
+		}
+
+		private DocumentModel _activeDocument = null;
+		public DocumentModel ActiveDocument {
+			get {
+				return _activeDocument;
+			}
+			set {
+				if (_activeDocument != value) {
+					_activeDocument = value;
+					RaisePropertyChanged(nameof(ActiveDocument));
+				}
+			}
+		}
+
+		protected void RaisePropertyChanged(string propertyName)
+		{
+			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+		}
+	}
+}

ILSpy/Docking/DockingHelper.cs

@@ -1,4 +1,5 @@
-using System.Windows;
+using System.Linq;
+using System.Windows;
 using System.Windows.Controls;
 using Xceed.Wpf.AvalonDock.Layout;
 
@@ -6,7 +7,18 @@ namespace ICSharpCode.ILSpy.Docking
 {
 	public static class DockingHelper
 	{
-		public static void DockHorizontal(LayoutContent layoutContent, ILayoutElement paneRelativeTo, GridLength dockHeight, bool dockBefore = false)
+		public static bool Dock(LayoutRoot root, LayoutContent layoutContent, PanePosition position)
+		{
+			var documentPane = root.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
+			if ((position == PanePosition.Top) || (position == PanePosition.Bottom)) {
+				return DockHorizontal(layoutContent, documentPane, new GridLength(200), position == PanePosition.Top);
+			} else if ((position == PanePosition.Left) || (position == PanePosition.Right)) {
+				return DockVertical(layoutContent as LayoutAnchorable, documentPane, new GridLength(400), position == PanePosition.Left);
+			}
+			return false;
+		}
+
+		public static bool DockHorizontal(LayoutContent layoutContent, ILayoutElement paneRelativeTo, GridLength dockHeight, bool dockBefore = false)
 		{
 			if (paneRelativeTo is ILayoutDocumentPane parentDocumentPane) {
 				var parentDocumentGroup = paneRelativeTo.FindParent<LayoutDocumentPaneGroup>();
@@ -22,11 +34,39 @@ namespace ICSharpCode.ILSpy.Docking
 				parentDocumentGroup.InsertChildAt(dockBefore ? indexOfParentPane : indexOfParentPane + 1, layoutDocumentPane);
 				layoutContent.IsActive = true;
 				layoutContent.Root.CollectGarbage();
-				Application.Current.MainWindow.Dispatcher.Invoke(() => {
+				Application.Current.MainWindow.Dispatcher.Invoke(
+					() => layoutDocumentPane.DockHeight = dockHeight,
+					System.Windows.Threading.DispatcherPriority.Loaded);
+				return true;
+			}
+
+			return false;
+		}
+
+		public static bool DockVertical(LayoutAnchorable anchorable, ILayoutElement paneRelativeTo, GridLength dockWidth, bool dockBefore = false)
+		{
+			if (paneRelativeTo is ILayoutDocumentPane parentDocumentPane) {
+				var grandParent = parentDocumentPane.Parent as LayoutPanel;
+				var targetAnchorablePane = grandParent.Children.OfType<LayoutAnchorablePane>().FirstOrDefault();
+				if (targetAnchorablePane == null) {
+					targetAnchorablePane = new LayoutAnchorablePane() {
+						DockWidth = new GridLength(400)
+					};
+					int targetIndex = dockBefore ? 0 : grandParent.ChildrenCount;
+					grandParent.InsertChildAt(targetIndex, targetAnchorablePane);
+				}
+				grandParent.Orientation = Orientation.Horizontal;
+				targetAnchorablePane.Children.Add(anchorable);
 
-					layoutDocumentPane.DockHeight = dockHeight;
-				}, System.Windows.Threading.DispatcherPriority.Loaded);
+				anchorable.IsActive = true;
+				anchorable.Root.CollectGarbage();
+				Application.Current.MainWindow.Dispatcher.Invoke(
+					() => targetAnchorablePane.DockWidth = dockWidth,
+					System.Windows.Threading.DispatcherPriority.Loaded);
+				return true;
 			}
+
+			return false;
 		}
 	}
 }

ILSpy/Docking/LayoutUpdateStrategy.cs

@@ -0,0 +1,42 @@
+using System.Linq;
+using System.Windows;
+using ICSharpCode.ILSpy.ViewModels;
+using Xceed.Wpf.AvalonDock.Layout;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class LayoutUpdateStrategy : ILayoutUpdateStrategy
+	{
+		public bool BeforeInsertAnchorable(LayoutRoot layout, LayoutAnchorable anchorableToShow, ILayoutContainer destinationContainer)
+		{
+			if ((destinationContainer != null) &&
+				(destinationContainer.FindParent<LayoutFloatingWindow>() != null))
+				return false;
+
+			PanePosition targetPosition = PanePosition.Top;
+			switch (anchorableToShow.Content) {
+				case AnalyzerPaneModel _:
+					targetPosition = PanePosition.Bottom;
+					break;
+				case AssemblyListPaneModel _:
+					targetPosition = PanePosition.Left;
+					break;
+			}
+
+			return DockingHelper.Dock(layout, anchorableToShow, targetPosition);
+		}
+
+		public void AfterInsertAnchorable(LayoutRoot layout, LayoutAnchorable anchorableShown)
+		{
+		}
+
+		public bool BeforeInsertDocument(LayoutRoot layout, LayoutDocument anchorableToShow, ILayoutContainer destinationContainer)
+		{
+			return false;
+		}
+
+		public void AfterInsertDocument(LayoutRoot layout, LayoutDocument anchorableShown)
+		{
+		}
+	}
+}

ILSpy/Docking/PaneCollection.cs

@@ -0,0 +1,43 @@
+using System.Collections;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
+using System.Linq;
+using ICSharpCode.ILSpy.ViewModels;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class PaneCollection<T> : INotifyCollectionChanged, INotifyPropertyChanged, ICollection<T>
+		where T : PaneModel
+	{
+		private ObservableCollection<T> observableCollection = new ObservableCollection<T>();
+
+		public event NotifyCollectionChangedEventHandler CollectionChanged;
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		public PaneCollection()
+		{
+			observableCollection.CollectionChanged += (sender, e) => CollectionChanged?.Invoke(this, e);
+		}
+
+		public void Add(T item)
+		{
+			if (!this.Any(pane => pane.ContentId == item.ContentId)) {
+				observableCollection.Add(item);
+			}
+
+			item.IsVisible = true;
+			item.IsActive = true;
+		}
+
+		public int Count => observableCollection.Count();
+		public bool IsReadOnly => false;
+		public void Clear() => observableCollection.Clear();
+		public bool Contains(T item) => observableCollection.Contains(item);
+		public void CopyTo(T[] array, int arrayIndex) => observableCollection.CopyTo(array, arrayIndex);
+		public bool Remove(T item) => observableCollection.Remove(item);
+		public IEnumerator<T> GetEnumerator() => observableCollection.GetEnumerator();
+		IEnumerator IEnumerable.GetEnumerator() => observableCollection.GetEnumerator();
+	}
+}

ILSpy/Docking/PanePosition.cs

@@ -4,6 +4,8 @@
 	{
 		Top,
 		Bottom,
+		Left,
+		Right,
 		Document
 	}
 }

ILSpy/Docking/PaneStyleSelector.cs

@@ -0,0 +1,24 @@
+using System.Windows;
+using System.Windows.Controls;
+using ICSharpCode.ILSpy.ViewModels;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class PaneStyleSelector : StyleSelector
+	{
+		public Style ToolPaneStyle { get; set; }
+
+		public Style DocumentStyle { get; set; }
+
+		public override Style SelectStyle(object item, DependencyObject container)
+		{
+			if (item is DocumentModel)
+				return DocumentStyle;
+
+			if (item is ToolPaneModel)
+				return ToolPaneStyle;
+
+			return base.SelectStyle(item, container);
+		}
+	}
+}

ILSpy/Docking/PaneTemplateSelector.cs

@@ -0,0 +1,25 @@
+using System;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Windows;
+using System.Windows.Controls;
+
+namespace ICSharpCode.ILSpy.Docking
+{
+	public class TemplateMapping
+	{
+		public Type Type { get; set; }
+		public DataTemplate Template { get; set; }
+	}
+
+	public class PaneTemplateSelector : DataTemplateSelector
+	{
+		public Collection<TemplateMapping> Mappings { get; set; } = new Collection<TemplateMapping>();
+
+		public override DataTemplate SelectTemplate(object item, DependencyObject container)
+		{
+			return Mappings.FirstOrDefault(m => m.Type == item.GetType())?.Template
+				?? base.SelectTemplate(item, container);
+		}
+	}
+}

ILSpy/ILSpy.csproj

@@ -138,8 +138,20 @@
     <Compile Include="DebugSteps.xaml.cs">
       <DependentUpon>DebugSteps.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Docking\ActiveDocumentConverter.cs" />
+    <Compile Include="ViewModels\AssemblyListPaneModel.cs" />
     <Compile Include="Docking\DockingHelper.cs" />
     <Compile Include="Docking\DockLayoutSettings.cs" />
+    <Compile Include="ViewModels\DocumentModel.cs" />
+    <Compile Include="Docking\LayoutUpdateStrategy.cs" />
+    <Compile Include="Docking\PaneCollection.cs" />
+    <Compile Include="ViewModels\PaneModel.cs" />
+    <Compile Include="Docking\PaneStyleSelector.cs" />
+    <Compile Include="Docking\PaneTemplateSelector.cs" />
+    <Compile Include="ViewModels\DebugStepsPaneModel.cs" />
+    <Compile Include="ViewModels\AnalyzerPaneModel.cs" />
+    <Compile Include="ViewModels\SearchPaneModel.cs" />
+    <Compile Include="ViewModels\ToolPaneModel.cs" />
     <Compile Include="ILSpyTraceListener.cs" />
     <Compile Include="DecompilationOptions.cs" />
     <Compile Include="ExtensionMethods.cs" />
@@ -252,6 +264,7 @@
     <Compile Include="TreeNodes\ResourceNodes\XmlResourceNode.cs" />
     <Compile Include="TreeNodes\SearchMsdnContextMenuEntry.cs" />
     <Compile Include="Analyzers\Builtin\TypeExtensionMethodsAnalyzer.cs" />
+    <Compile Include="Docking\DockWorkspace.cs" />
     <EmbeddedResource Include="..\doc\LGPL.txt">
       <Link>LGPL.txt</Link>
     </EmbeddedResource>

ILSpy/MainWindow.xaml

@@ -5,8 +5,11 @@
 	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:tv="clr-namespace:ICSharpCode.TreeView;assembly=ICSharpCode.TreeView"
 	xmlns:local="clr-namespace:ICSharpCode.ILSpy"
 	xmlns:avalondock="http://schemas.xceed.com/wpf/xaml/avalondock"
+	xmlns:docking="clr-namespace:ICSharpCode.ILSpy.Docking"
 	xmlns:controls="clr-namespace:ICSharpCode.ILSpy.Controls"
-	xmlns:properties="clr-namespace:ICSharpCode.ILSpy.Properties"	
+	xmlns:analyzers="clr-namespace:ICSharpCode.ILSpy.Analyzers"
+	xmlns:properties="clr-namespace:ICSharpCode.ILSpy.Properties"
+	xmlns:viewmodels="clr-namespace:ICSharpCode.ILSpy.ViewModels"
 	Title="ILSpy"
 	MinWidth="250"
 	MinHeight="200"
@@ -18,7 +21,46 @@
 >
 	<Window.Resources>
 		<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" />
+		<docking:ActiveDocumentConverter x:Key="ActiveDocumentConverter"/>
+
+		<tv:SharpTreeView x:Key="TreeView"
+				AutomationProperties.Name="Assemblies and Classes"
+				SelectionChanged="TreeView_SelectionChanged"
+				ShowRoot="False"
+				AllowDropOrder="True"
+				AllowDrop="True"
+				BorderThickness="0,1,1,1" Visibility="Visible" />
+		
+		<DataTemplate x:Key="AssemblyListPaneTemplate">
+			<ContentControl Content="{StaticResource TreeView}" />
+		</DataTemplate>
+
+		<local:DebugSteps x:Key="DebugSteps" />
+
+		<DataTemplate x:Key="DebugStepsPaneTemplate">
+			<ContentControl Content="{StaticResource DebugSteps}" />
+		</DataTemplate>
+
+		<local:SearchPane x:Key="SearchPane" />
+		
+		<DataTemplate x:Key="SearchPaneTemplate">
+			<ContentControl Content="{StaticResource SearchPane}" />
+		</DataTemplate>
+		
+		<analyzers:AnalyzerTreeView x:Key="AnalyzerTreeView" />
+
+		<DataTemplate x:Key="AnalyzerPaneTemplate">
+			<ContentControl Content="{StaticResource AnalyzerTreeView}" />
+		</DataTemplate>
+
+		<ContentPresenter x:Key="MainPane" />
+
+		<DataTemplate x:Key="DecompilerTextViewTemplate">
+			<!-- decompilerTextView is inserted into the mainPane by code -->
+			<ContentControl Content="{StaticResource MainPane}" />
+		</DataTemplate>
 	</Window.Resources>
+
 	<Window.CommandBindings>
 		<CommandBinding
 			Command="Open"
@@ -54,9 +96,9 @@
 			<MenuItem Header="{x:Static properties:Resources._File}" />
 			<!-- contents of file menu are added using MEF -->
 			<MenuItem Header="{x:Static properties:Resources._View}">
-				<MenuItem Header="{x:Static properties:Resources.Show_publiconlyTypesMembers}" IsCheckable="True" IsChecked="{Binding FilterSettings.ApiVisPublicOnly}" />
-				<MenuItem Header="{x:Static properties:Resources.Show_internalTypesMembers}" IsCheckable="True" IsChecked="{Binding FilterSettings.ApiVisPublicAndInternal}" />
-				<MenuItem Header="{x:Static properties:Resources.Show_allTypesAndMembers}" IsCheckable="True" IsChecked="{Binding FilterSettings.ApiVisAll}" />
+				<MenuItem Header="{x:Static properties:Resources.Show_publiconlyTypesMembers}" IsCheckable="True" IsChecked="{Binding SessionSettings.FilterSettings.ApiVisPublicOnly}" />
+				<MenuItem Header="{x:Static properties:Resources.Show_internalTypesMembers}" IsCheckable="True" IsChecked="{Binding SessionSettings.FilterSettings.ApiVisPublicAndInternal}" />
+				<MenuItem Header="{x:Static properties:Resources.Show_allTypesAndMembers}" IsCheckable="True" IsChecked="{Binding SessionSettings.FilterSettings.ApiVisAll}" />
 			</MenuItem>
 		</Menu>
 		<!-- ToolBar -->
@@ -79,23 +121,23 @@
 			<Separator />
 			<!-- 'Open' toolbar category is inserted here -->
 			<Separator />
-			<CheckBox IsChecked="{Binding FilterSettings.ApiVisPublicOnly}" ToolTip="{x:Static properties:Resources.ShowPublicOnlyTypesMembers}">
+			<CheckBox IsChecked="{Binding SessionSettings.FilterSettings.ApiVisPublicOnly}" ToolTip="{x:Static properties:Resources.ShowPublicOnlyTypesMembers}">
 				<Image Width="16" Height="16" Source="{controls:XamlResource Images/ShowPublicOnly}" />
 			</CheckBox>
-			<CheckBox IsChecked="{Binding FilterSettings.ApiVisPublicAndInternal}" ToolTip="{x:Static properties:Resources.ShowInternalTypesMembers}">
+			<CheckBox IsChecked="{Binding SessionSettings.FilterSettings.ApiVisPublicAndInternal}" ToolTip="{x:Static properties:Resources.ShowInternalTypesMembers}">
 				<Image Width="16" Height="16" Source="{controls:XamlResource Images/ShowPrivateInternal}" />
 			</CheckBox>
-			<CheckBox IsChecked="{Binding FilterSettings.ApiVisAll}" ToolTip="{x:Static properties:Resources.ShowAllTypesAndMembers}">
+			<CheckBox IsChecked="{Binding SessionSettings.FilterSettings.ApiVisAll}" ToolTip="{x:Static properties:Resources.ShowAllTypesAndMembers}">
 				<Image Width="16" Height="16" Source="{controls:XamlResource Images/ShowAll}" />
 			</CheckBox>
 			<Separator />
 			<ComboBox Name="languageComboBox" DisplayMemberPath="Name" Width="100" MaxDropDownHeight="Auto"
 			          ItemsSource="{x:Static local:Languages.AllLanguages}" ToolTip="{x:Static properties:Resources.SelectLanguageDropdownTooltip}"
-			          SelectedItem="{Binding FilterSettings.Language}"/>
+			          SelectedItem="{Binding SessionSettings.FilterSettings.Language}"/>
 			<ComboBox Name="languageVersionComboBox" DisplayMemberPath="DisplayName" Width="120" MaxDropDownHeight="Auto" ToolTip="{x:Static properties:Resources.SelectVersionDropdownTooltip}"
 			          Visibility="{Binding SelectedItem.HasLanguageVersions, ElementName=languageComboBox, Converter={StaticResource BooleanToVisibilityConverter}}"
 			          ItemsSource="{Binding SelectedItem.LanguageVersions, ElementName=languageComboBox, UpdateSourceTrigger=PropertyChanged}"
-			          SelectedItem="{Binding FilterSettings.LanguageVersion, UpdateSourceTrigger=PropertyChanged}"/>
+			          SelectedItem="{Binding SessionSettings.FilterSettings.LanguageVersion, UpdateSourceTrigger=PropertyChanged}"/>
 		</ToolBar>
 		<Border DockPanel.Dock="Top" BorderBrush="Black" BorderThickness="1" Name="updatePanel" Visibility="Collapsed">
 			<DockPanel KeyboardNavigation.TabNavigation="Contained">
@@ -116,41 +158,61 @@
 				           Text="{x:Static properties:Resources.StandBy}"/>
 			</StatusBarItem>
 		</StatusBar>
-		<!-- Main grid separating left pane (treeView) from main pane (textEditor) -->
 
 		<avalondock:DockingManager x:Name="DockManager"
-                    AllowMixedOrientation="True" Grid.ColumnSpan="2">
-
-			<avalondock:LayoutRoot x:Name="LayoutRoot" >
-				<avalondock:LayoutPanel Orientation="Vertical">
-					<avalondock:LayoutPanel Orientation="Horizontal">
-						<avalondock:LayoutAnchorablePaneGroup DockWidth="400" Orientation="Vertical">
-							<avalondock:LayoutAnchorablePane DockHeight="*">
-								<avalondock:LayoutAnchorable x:Name="Tree" Title="Assemblies" CanHide="False" CanClose="False">
-									<!-- Left pane: Tree View of assemblies and classes -->
-									<tv:SharpTreeView
-										Name="treeView"
-										AutomationProperties.Name="Assemblies and Classes"
-										SelectionChanged="TreeView_SelectionChanged"
-										ShowRoot="False"
-										AllowDropOrder="True"
-										AllowDrop="True"
-										BorderThickness="0,1,1,1" Visibility="Visible" />
-								</avalondock:LayoutAnchorable>
-							</avalondock:LayoutAnchorablePane>
-						</avalondock:LayoutAnchorablePaneGroup>
+								   DataContext="{Binding Workspace}"
+								   AnchorablesSource="{Binding ToolPanes}" 
+                                   DocumentsSource="{Binding Documents}"
+                                   ActiveContent="{Binding ActiveDocument, Mode=Default, Converter={StaticResource ActiveDocumentConverter}}"
+								   AllowMixedOrientation="True">
 
-						<avalondock:LayoutDocumentPaneGroup DockWidth="*">
-							<avalondock:LayoutDocumentPane x:Name="adDocumentPane">
-								<avalondock:LayoutDocument Title="View" CanClose="False">
-									<!-- decompilerTextView is into the mainPane by code -->
-									<ContentPresenter Name="mainPane" />
-								</avalondock:LayoutDocument>
-							</avalondock:LayoutDocumentPane>
-						</avalondock:LayoutDocumentPaneGroup>
-					</avalondock:LayoutPanel>
+			<avalondock:LayoutRoot>
+					<avalondock:LayoutPanel Orientation="Vertical">
+						<avalondock:LayoutDocumentPane />
 				</avalondock:LayoutPanel>
 			</avalondock:LayoutRoot>
+
+			<avalondock:DockingManager.LayoutUpdateStrategy>
+				<docking:LayoutUpdateStrategy />
+			</avalondock:DockingManager.LayoutUpdateStrategy>
+
+			<avalondock:DockingManager.LayoutItemTemplateSelector>
+				<docking:PaneTemplateSelector>
+					<docking:PaneTemplateSelector.Mappings>
+						<docking:TemplateMapping Type="{x:Type viewmodels:AssemblyListPaneModel}" Template="{StaticResource AssemblyListPaneTemplate}" />
+						<docking:TemplateMapping Type="{x:Type viewmodels:SearchPaneModel}" Template="{StaticResource SearchPaneTemplate}" />
+						<docking:TemplateMapping Type="{x:Type viewmodels:DebugStepsPaneModel}" Template="{StaticResource DebugStepsPaneTemplate}" />
+						<docking:TemplateMapping Type="{x:Type viewmodels:AnalyzerPaneModel}" Template="{StaticResource AnalyzerPaneTemplate}" />
+						<docking:TemplateMapping Type="{x:Type viewmodels:DocumentModel}" Template="{StaticResource DecompilerTextViewTemplate}" />
+					</docking:PaneTemplateSelector.Mappings>
+				</docking:PaneTemplateSelector>
+			</avalondock:DockingManager.LayoutItemTemplateSelector>
+
+			<avalondock:DockingManager.LayoutItemContainerStyleSelector>
+				<docking:PaneStyleSelector>
+					<docking:PaneStyleSelector.ToolPaneStyle>
+						<Style TargetType="{x:Type avalondock:LayoutAnchorableItem}">
+							<Setter Property="Title" Value="{Binding Model.Title}"/>
+							<Setter Property="Visibility" Value="{Binding Model.IsVisible, Mode=TwoWay, Converter={StaticResource BooleanToVisibilityConverter}, ConverterParameter={x:Static Visibility.Hidden}}"/>
+							<Setter Property="ContentId" Value="{Binding Model.ContentId}"/>
+							<Setter Property="IsSelected" Value="{Binding Model.IsSelected, Mode=TwoWay}"/>
+							<Setter Property="IsActive" Value="{Binding Model.IsActive, Mode=TwoWay}"/>
+							<Setter Property="CanClose" Value="{Binding Model.IsCloseable, Mode=TwoWay}" />
+							<Setter Property="CanHide" Value="{Binding Model.IsCloseable}" />
+						</Style>
+					</docking:PaneStyleSelector.ToolPaneStyle>
+					<docking:PaneStyleSelector.DocumentStyle>
+						<Style TargetType="{x:Type avalondock:LayoutItem}">
+							<Setter Property="Title" Value="{Binding Model.Title}"/>
+							<Setter Property="Visibility" Value="{Binding Model.IsVisible, Mode=TwoWay, Converter={StaticResource BooleanToVisibilityConverter}, ConverterParameter={x:Static Visibility.Hidden}}"/>
+							<Setter Property="ContentId" Value="{Binding Model.ContentId}"/>
+							<Setter Property="IsSelected" Value="{Binding Model.IsSelected, Mode=TwoWay}"/>
+							<Setter Property="IsActive" Value="{Binding Model.IsActive, Mode=TwoWay}"/>
+							<Setter Property="CanClose" Value="{Binding Model.IsCloseable, Mode=TwoWay}" />
+						</Style>
+					</docking:PaneStyleSelector.DocumentStyle>
+				</docking:PaneStyleSelector>
+			</avalondock:DockingManager.LayoutItemContainerStyleSelector>
 		</avalondock:DockingManager>
 	</DockPanel>
 </Window>

ILSpy/MainWindow.xaml.cs

@@ -38,9 +38,12 @@ using ICSharpCode.Decompiler.Documentation;
 using ICSharpCode.Decompiler.Metadata;
 using ICSharpCode.Decompiler.TypeSystem;
 using ICSharpCode.Decompiler.TypeSystem.Implementation;
+using ICSharpCode.ILSpy.Analyzers;
 using ICSharpCode.ILSpy.Controls;
+using ICSharpCode.ILSpy.Docking;
 using ICSharpCode.ILSpy.TextView;
 using ICSharpCode.ILSpy.TreeNodes;
+using ICSharpCode.ILSpy.ViewModels;
 using ICSharpCode.TreeView;
 using Microsoft.Win32;
 using OSVersionHelper;
@@ -49,6 +52,12 @@ using Xceed.Wpf.AvalonDock.Layout.Serialization;
 
 namespace ICSharpCode.ILSpy
 {
+	class MainWindowDataContext
+	{
+		public DockWorkspace Workspace { get; set; }
+		public SessionSettings SessionSettings { get; set; }
+	}
+
 	/// <summary>
 	/// The main window of the application.
 	/// </summary>
@@ -76,6 +85,30 @@ namespace ICSharpCode.ILSpy
 			get { return sessionSettings; }
 		}
 
+		public ContentPresenter mainPane {
+			get {
+				return FindResource("MainPane") as ContentPresenter;
+			}
+		}
+
+		public SharpTreeView treeView {
+			get {
+				return FindResource("TreeView") as SharpTreeView;
+			}
+		}
+
+		public AnalyzerTreeView AnalyzerTreeView {
+			get {
+				return FindResource("AnalyzerTreeView") as AnalyzerTreeView;
+			}
+		}
+
+		public SearchPane SearchPane {
+			get {
+				return FindResource("SearchPane") as SearchPane;
+			}
+		}
+
 		public MainWindow()
 		{
 			instance = this;
@@ -86,9 +119,13 @@ namespace ICSharpCode.ILSpy
 
 			this.Icon = new BitmapImage(new Uri("pack://application:,,,/ILSpy;component/images/ILSpy.ico"));
 
-			this.DataContext = sessionSettings;
+			this.DataContext = new MainWindowDataContext {
+				Workspace = DockWorkspace.Instance,
+				SessionSettings = sessionSettings
+			};
 
 			InitializeComponent();
+
 			decompilerTextView = App.ExportProvider.GetExportedValue<DecompilerTextView>();
 			mainPane.Content = decompilerTextView;
 
@@ -295,8 +332,8 @@ namespace ICSharpCode.ILSpy
 			commandLineLoadedAssemblies.Clear(); // clear references once we don't need them anymore
 			NavigateOnLaunch(args.NavigateTo, sessionSettings.ActiveTreeViewPath, spySettings, relevantAssemblies);
 			if (args.Search != null) {
-				SearchPane.Instance.SearchTerm = args.Search;
-				SearchPane.Instance.Show();
+				SearchPane.SearchTerm = args.Search;
+				SearchPane.Show();
 			}
 		}
 
@@ -877,7 +914,7 @@ namespace ICSharpCode.ILSpy
 
 		void SearchCommandExecuted(object sender, ExecutedRoutedEventArgs e)
 		{
-			SearchPane.Instance.Show();
+			DockWorkspace.Instance.ToolPanes.Add(SearchPaneModel.Instance);
 		}
 		#endregion
 
@@ -1037,22 +1074,22 @@ namespace ICSharpCode.ILSpy
 			return loadedAssy.FileName;
 		}
 
-		#region Top/Bottom Pane management
+		//#region Top/Bottom Pane management
 
-		public void ShowInNewPane(string title, object content, PanePosition panePosition, string toolTip = null)
-		{
-			if (panePosition == PanePosition.Document) {
-				var layoutDocument = new LayoutDocument() { Title = title, Content = content, ToolTip = toolTip, CanClose = true };
-				var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
-				documentPane.Children.Add(layoutDocument);
-			} else {
-				var layoutAnchorable = new LayoutAnchorable() { Title = title, Content = content, ToolTip = toolTip, CanClose = true, CanHide = true };
-				var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
-				Docking.DockingHelper.DockHorizontal(layoutAnchorable, documentPane, new GridLength(200), panePosition == PanePosition.Top);
-			}
-		}
+		//public void ShowInNewPane(string title, object content, PanePosition panePosition, string toolTip = null)
+		//{
+		//	if (panePosition == PanePosition.Document) {
+		//		var layoutDocument = new LayoutDocument() { Title = title, Content = content, ToolTip = toolTip, CanClose = true };
+		//		var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
+		//		documentPane.Children.Add(layoutDocument);
+		//	} else {
+		//		var layoutAnchorable = new LayoutAnchorable() { Title = title, Content = content, ToolTip = toolTip, CanClose = true, CanHide = true };
+		//		var documentPane = this.DockManager.Layout.Descendents().OfType<LayoutDocumentPane>().FirstOrDefault();
+		//		Docking.DockingHelper.DockHorizontal(layoutAnchorable, documentPane, new GridLength(200), panePosition == PanePosition.Top);
+		//	}
+		//}
 
-		#endregion
+		//#endregion
 
 		public void UnselectAll()
 		{
@@ -1076,5 +1113,10 @@ namespace ICSharpCode.ILSpy
 		{
 			return toolBar.Items;
 		}
+
+		private void DockManager_DocumentClosed(object sender, Xceed.Wpf.AvalonDock.DocumentClosedEventArgs e)
+		{
+
+		}
 	}
 }

ILSpy/Search/SearchPane.cs

@@ -31,7 +31,9 @@ using System.Windows.Input;
 using System.Windows.Media;
 using System.Windows.Threading;
 using ICSharpCode.Decompiler.TypeSystem;
+using ICSharpCode.ILSpy.Docking;
 using ICSharpCode.ILSpy.Search;
+using ICSharpCode.ILSpy.ViewModels;
 
 namespace ICSharpCode.ILSpy
 {
@@ -42,7 +44,6 @@ namespace ICSharpCode.ILSpy
 	{
 		const int MAX_RESULTS = 1000;
 		const int MAX_REFRESH_TIME_MS = 10; // More means quicker forward of data, less means better responsibility
-		static SearchPane instance;
 		RunningSearch currentSearch;
 		bool runSearchOnNextShow;
 
@@ -53,17 +54,7 @@ namespace ICSharpCode.ILSpy
 			get { return (ObservableCollection<SearchResult>)GetValue(ResultsProperty); }
 		}
 
-		public static SearchPane Instance {
-			get {
-				if (instance == null) {
-					App.Current.VerifyAccess();
-					instance = new SearchPane();
-				}
-				return instance;
-			}
-		}
-		
-		private SearchPane()
+		public SearchPane()
 		{
 			InitializeComponent();
 			searchModeComboBox.Items.Add(new { Image = Images.Library, Name = "Types and Members" });
@@ -114,7 +105,7 @@ namespace ICSharpCode.ILSpy
 		public void Show()
 		{
 			if (!IsVisible) {
-				MainWindow.Instance.ShowInNewPane(Properties.Resources.SearchPane_Search, this, PanePosition.Top);
+				DockWorkspace.Instance.ToolPanes.Add(SearchPaneModel.Instance);
 				if (runSearchOnNextShow) {
 					runSearchOnNextShow = false;
 					StartSearch(this.SearchTerm);

ILSpy/ViewModels/AnalyzerPaneModel.cs

@@ -0,0 +1,15 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class AnalyzerPaneModel : ToolPaneModel
+	{
+		public const string PaneContentId = "analyzerPane";
+
+		public static AnalyzerPaneModel Instance { get; } = new AnalyzerPaneModel();
+
+		private AnalyzerPaneModel()
+		{
+			ContentId = PaneContentId;
+			Title = Properties.Resources.Analyze;
+		}
+	}
+}

ILSpy/ViewModels/AssemblyListPaneModel.cs

@@ -0,0 +1,16 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class AssemblyListPaneModel : ToolPaneModel
+	{
+		public const string PaneContentId = "assemblyListPane";
+
+		public static AssemblyListPaneModel Instance { get; } = new AssemblyListPaneModel();
+
+		private AssemblyListPaneModel()
+		{
+			Title = "Assemblies";
+			ContentId = PaneContentId;
+			IsCloseable = false;
+		}
+	}
+}

ILSpy/ViewModels/DebugStepsPaneModel.cs

@@ -0,0 +1,15 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class DebugStepsPaneModel : ToolPaneModel
+	{
+		public const string PaneContentId = "debugStepsPane";
+
+		public static DebugStepsPaneModel Instance { get; } = new DebugStepsPaneModel();
+
+		private DebugStepsPaneModel()
+		{
+			ContentId = PaneContentId;
+			Title = Properties.Resources.DebugSteps;
+		}
+	}
+}

ILSpy/ViewModels/DocumentModel.cs

@@ -0,0 +1,12 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class DocumentModel : PaneModel
+	{
+		public DocumentModel()
+		{
+			ContentId = "document";
+			Title = "View";
+			IsCloseable = false;
+		}
+	}
+}

ILSpy/ViewModels/PaneModel.cs

@@ -0,0 +1,80 @@
+using System.ComponentModel;
+
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class PaneModel : INotifyPropertyChanged
+	{
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		protected void RaisePropertyChanged(string propertyName)
+		{
+			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+		}
+
+		private bool isSelected = false;
+		public bool IsSelected {
+			get => isSelected;
+			set {
+				if (isSelected != value) {
+					isSelected = value;
+					RaisePropertyChanged(nameof(IsSelected));
+				}
+			}
+		}
+
+		private bool isActive = false;
+		public bool IsActive {
+			get => isActive;
+			set {
+				if (isActive != value) {
+					isActive = value;
+					RaisePropertyChanged(nameof(IsActive));
+				}
+			}
+		}
+
+		private bool isVisible = true;
+		public bool IsVisible {
+			get { return isVisible; }
+			set {
+				if (isVisible != value) {
+					isVisible = value;
+					RaisePropertyChanged(nameof(IsVisible));
+				}
+			}
+		}
+
+		private bool isCloseable = true;
+		public bool IsCloseable {
+			get { return isCloseable; }
+			set {
+				if (isCloseable != value) {
+					isCloseable = value;
+					RaisePropertyChanged(nameof(IsCloseable));
+				}
+			}
+		}
+
+		private string contentId;
+		public string ContentId {
+			get => contentId;
+			set {
+				if (contentId != value) {
+					contentId = value;
+					RaisePropertyChanged(nameof(ContentId));
+				}
+			}
+		}
+
+		private string title;
+		public string Title {
+			get => title;
+			set {
+				if (title != value) {
+					title = value;
+					RaisePropertyChanged(nameof(Title));
+				}
+			}
+		}
+	}
+}

ILSpy/ViewModels/SearchPaneModel.cs

@@ -0,0 +1,16 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class SearchPaneModel : ToolPaneModel
+	{
+		public const string PaneContentId = "searchPane";
+
+		public static SearchPaneModel Instance { get; } = new SearchPaneModel();
+
+		private SearchPaneModel()
+		{
+			ContentId = PaneContentId;
+			Title = Properties.Resources.SearchPane_Search;
+			IsCloseable = true;
+		}
+	}
+}

ILSpy/ViewModels/ToolPaneModel.cs

@@ -0,0 +1,7 @@
+namespace ICSharpCode.ILSpy.ViewModels
+{
+	public class ToolPaneModel : PaneModel
+	{
+
+	}
+}