Wire the dock factory's locators eagerly before the chrome

Build the layout and call InitLayout up front in DockWorkspace instead of
letting DockControl run it post-template-apply, and populate the locators
explicitly: tool panes map their id to the [Shared] singleton pane, the
Documents dock and main tab get entries for navigate-by-id, and
HostWindowLocator is registered so panes can float into their own windows.
Doing it before the chrome attaches keeps the layout's owner/factory
wiring ahead of the first content realisation.

Also drops the now-redundant per-VM DataTemplate blocks from App.axaml --
the single ViewLocator already resolves them -- and the unused
MainWindowViewModel.DockFactory property and DockControl init flags.

Assisted-by: Claude:claude-opus-4-8:Claude Code

ILSpy/App.axaml

@@ -8,7 +8,6 @@
              xmlns:compare="using:ILSpy.Compare"
              xmlns:textView="using:ILSpy.TextView"
              xmlns:metaViews="using:ILSpy.Views"
-             xmlns:vm="using:ILSpy.ViewModels"
              xmlns:dockTheme="using:Dock.Avalonia.Themes.Simple"
              xmlns:recycling="using:Avalonia.Controls.Recycling"
              xmlns:docking="using:ILSpy.Docking"
@@ -47,30 +46,9 @@
     </Application.Resources>
 
     <Application.DataTemplates>
-        <DataTemplate DataType="tree:AssemblyTreeModel">
-            <tree:AssemblyListPane />
-        </DataTemplate>
-        <DataTemplate DataType="search:SearchPaneModel">
-            <search:SearchPane />
-        </DataTemplate>
-        <DataTemplate DataType="analyzers:AnalyzerTreeViewModel">
-            <analyzers:AnalyzerTreeView />
-        </DataTemplate>
-        <DataTemplate DataType="vm:ContentTabPage">
-            <metaViews:ContentTabPageView />
-        </DataTemplate>
-        <DataTemplate DataType="textView:DecompilerTabPageModel">
-            <textView:DecompilerTextView />
-        </DataTemplate>
-        <DataTemplate DataType="vm:MetadataTablePageModel">
-            <metaViews:MetadataTablePage />
-        </DataTemplate>
-        <DataTemplate DataType="vm:DebugStepsPaneModel">
-            <metaViews:DebugSteps />
-        </DataTemplate>
-        <DataTemplate DataType="compare:CompareTabPageModel">
-            <compare:CompareView />
-        </DataTemplate>
+        <!-- ViewLocator handles every dockable VM (tool panes, document tab content,
+             ContentTabPage) plus any ViewModelBase-derived viewmodel, with one IDataTemplate
+             instance for all of them (see ViewLocator.cs). -->
         <local:ViewLocator/>
     </Application.DataTemplates>
 

ILSpy/Docking/DockWorkspace.cs

@@ -144,7 +144,7 @@ namespace ILSpy.Docking
 			NavigateToHistoryCommand = new RelayCommand<NavigationEntry>(NavigateToHistory,
 				entry => entry != null && (history.BackEntries.Contains(entry) || history.ForwardEntries.Contains(entry)));
 			ShowSearchCommand = new RelayCommand(ExecuteShowSearch);
-			using (ILSpy.AppEnv.AppLog.Phase("ILSpyDockFactory ctor + CreateLayout"))
+			using (ILSpy.AppEnv.AppLog.Phase("ILSpyDockFactory ctor + CreateLayout + InitLayout"))
 			{
 				factory = new ILSpyDockFactory(toolPaneRegistry);
 				// Prefer the user's saved layout (ILSpy.Layout.json sidecar next to
@@ -152,6 +152,11 @@ namespace ILSpy.Docking
 				// or it failed to deserialize. The fallback path is the same shape the
 				// app uses on first launch.
 				Layout = factory.LoadLayout(GetLayoutFilePath()) ?? factory.CreateLayout();
+				// Build the layout, then InitLayout BEFORE the chrome ever sees it, rather than
+				// letting the DockControl's InitializeFactory / InitializeLayout flags run it
+				// post-template-apply. Wiring owners/factories/locators up front means the
+				// layout is fully resolvable before the first DeferredContentControl attaches.
+				factory.InitLayout(Layout);
 			}
 
 			assemblyTreeModel.PropertyChanged += OnAssemblyTreePropertyChanged;
@@ -160,8 +165,6 @@ namespace ILSpy.Docking
 					ShowSelectedNode();
 			};
 			languageService.PropertyChanged += OnLanguagePropertyChanged;
-			// Layout/factory initialization (locators, parent/factory wiring) is done by
-			// the DockControl in MainWindow.axaml via InitializeFactory/InitializeLayout.
 
 			ToolPaneMenuItems = toolPaneRegistry.Panes
 				.Select(p => new ToolPaneMenuItem(p.Pane, factory))

ILSpy/Docking/ILSpyDockFactory.cs

@@ -21,6 +21,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 
+using Dock.Avalonia.Controls;
 using Dock.Model.Controls;
 using Dock.Model.Core;
 using Dock.Model.Mvvm;
@@ -49,6 +50,53 @@ namespace ILSpy.Docking
 			this.panes = registry.Panes;
 		}
 
+		/// <summary>
+		/// Populate the locator dictionaries with explicit id-to-factory mappings before the
+		/// base init wires owners/factories down the tree, rather than relying on
+		/// <see cref="DockControl.InitializeFactory"/> to populate them post-template-apply.
+		/// Wiring the locators (and the HostWindowLocator) up front means the layout is fully
+		/// resolvable before the chrome realises any content.
+		///
+		/// <para>
+		/// Tool panes are <c>[Shared]</c> MEF singletons, so the lambdas in
+		/// <see cref="IFactory.ContextLocator"/> / <see cref="IFactory.DockableLocator"/>
+		/// can safely return the cached pane instance for both context and dockable
+		/// lookup. Documents and the root dock get explicit entries for navigate-by-id
+		/// (<c>root.Navigate.Execute("Documents")</c>).
+		/// </para>
+		/// </summary>
+		public override void InitLayout(IDockable layout)
+		{
+			ContextLocator = new Dictionary<string, Func<object?>>();
+			DockableLocator = new Dictionary<string, Func<IDockable?>>();
+			HostWindowLocator = new Dictionary<string, Func<IHostWindow?>> {
+				[nameof(IDockWindow)] = () => new HostWindow()
+			};
+
+			// Tool panes: the VM is its own context (no separate model class), and the
+			// dockable IS the pane instance, so both locators map id → same singleton.
+			foreach (var entry in panes)
+			{
+				var pane = entry.Pane;
+				if (string.IsNullOrEmpty(pane.Id))
+					continue;
+				ContextLocator[pane.Id] = () => pane;
+				DockableLocator[pane.Id] = () => pane;
+			}
+
+			// Documents dock + the persistent main content tab — these are the structural
+			// slots ShowSelectedNode / OpenNewTab target. Carve-out tabs (per-node spawned
+			// ContentTabPages) don't get id mappings because they're transient.
+			if (Documents is { Id: { Length: > 0 } docsId } docs)
+				DockableLocator[docsId] = () => docs;
+			if (MainTab is { Id: { Length: > 0 } tabId } mainTab)
+				DockableLocator[tabId] = () => mainTab;
+			if (layout is IRootDock { Id: { Length: > 0 } rootId } root)
+				DockableLocator[rootId] = () => root;
+
+			base.InitLayout(layout);
+		}
+
 		/// <summary>
 		/// Serializes <paramref name="layout"/> to <paramref name="path"/> using
 		/// <see cref="ILSpyDockJson.Options"/>. Best-effort: any IO or serialization

ILSpy/ViewModels/MainWindowViewModel.cs

@@ -19,7 +19,6 @@
 using System.Composition;
 
 using Dock.Model.Controls;
-using Dock.Model.Core;
 
 using ILSpy.AssemblyTree;
 using ILSpy.Docking;
@@ -41,8 +40,6 @@ namespace ILSpy.ViewModels
 
 		public UpdatePanelViewModel UpdatePanel { get; }
 
-		public IFactory DockFactory => DockWorkspace.Factory;
-
 		public IRootDock DockLayout => DockWorkspace.Layout;
 
 		public System.Collections.Generic.IReadOnlyList<ToolPaneMenuItem> ToolPaneMenuItems => DockWorkspace.ToolPaneMenuItems;

ILSpy/Views/MainWindow.axaml

@@ -46,9 +46,6 @@
 			           Margin="8,0" Name="statusLabel" Text="Stand by..." />
 		</Border>
 
-		<dock:DockControl Layout="{Binding DockLayout}"
-		                  Factory="{Binding DockFactory}"
-		                  InitializeFactory="True"
-		                  InitializeLayout="True" />
+		<dock:DockControl Layout="{Binding DockLayout}" />
 	</DockPanel>
 </Window>