Options tab — live bindings, left tabs, font preview

Three changes:

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy.Tests/Options/OptionsTabTests.cs

@@ -128,12 +128,13 @@ public class OptionsTabTests
 	}
 
 	[AvaloniaTest]
-	public async Task Apply_Writes_Snapshot_Through_To_Live_DecompilerSettings()
+	public void Panel_Edits_Take_Effect_Immediately_On_Live_DecompilerSettings()
 	{
-		// Snapshot pattern: changes in the panel's settings instance don't reach the live
-		// service until Apply. After Apply, SettingsService.DecompilerSettings reflects the
-		// new value. Toggling a property on the snapshot copy alone shouldn't affect the
-		// live instance until Apply is called.
+		// Live-binding architecture (no snapshot): toggling a checkbox in the Decompiler
+		// panel mutates the live SettingsService.DecompilerSettings instance directly. No
+		// Apply step. Subscribers to DecompilerSettings.PropertyChanged see the change
+		// immediately; the next decompile pulls the new value via Clone() in
+		// DecompilerTabPageModel.
 		var window = AppComposition.Current.GetExport<MainWindow>();
 		window.Show();
 		var settings = AppComposition.Current.GetExport<SettingsService>();
@@ -149,26 +150,17 @@ public class OptionsTabTests
 			.OfType<ContentTabPage>().First(t => t.Content is OptionsPageModel).Content!;
 		var decompilerPage = (DecompilerSettingsViewModel)model.Pages[0];
 
-		// Find the UsingDeclarations item in the reflection-built tree and flip it.
+		// Flip UsingDeclarations through the panel viewmodel.
 		var usingDecl = decompilerPage.Settings
 			.SelectMany(g => g.Settings)
 			.First(s => s.Property.Name == nameof(global::ICSharpCode.Decompiler.DecompilerSettings.UsingDeclarations));
 		usingDecl.IsEnabled = !liveBefore;
 
-		// Live service unaffected so far — only the snapshot copy changed.
-		// Snapshot edits must not leak into the live service before Apply.
-		settings.DecompilerSettings.UsingDeclarations.Should().Be(liveBefore);
-
-		// Apply — flushes snapshot to XML and reloads sections so live values match.
-		model.ApplyCommand.Execute(null);
-		await Task.Yield();
-
-		// After Apply, the live service must see the panel's toggled value.
+		// Live service must see the change immediately — no Apply needed.
 		settings.DecompilerSettings.UsingDeclarations.Should().Be(!liveBefore);
 
-		// Clean-up: restore the original so the persisted XML doesn't pollute later tests.
+		// Clean-up: restore the original so the next test sees a clean slate.
 		usingDecl.IsEnabled = liveBefore;
-		model.ApplyCommand.Execute(null);
 	}
 
 	[AvaloniaTest]

ILSpy/Options/DecompilerSettingsViewModel.cs

@@ -58,9 +58,9 @@ namespace ILSpy.Options
 
 		DecompilerSettings decompilerSettings = null!;
 
-		public void Load(SettingsSnapshot snapshot)
+		public void Load(SettingsService settings)
 		{
-			decompilerSettings = snapshot.GetSettings<DecompilerSettings>();
+			decompilerSettings = settings.DecompilerSettings;
 			LoadSettings();
 		}
 

ILSpy/Options/DisplaySettingsPanel.axaml

@@ -20,8 +20,13 @@
 				               Value="{Binding Settings.SelectedFontSize, Mode=TwoWay}" />
 				<Border Grid.Row="1" Grid.Column="1" Grid.ColumnSpan="2"
 				        BorderBrush="#FFCCCEDB" BorderThickness="1" Padding="6" Margin="0,2,0,0">
+					<!-- FontFamily binds to a derived FontFamily property because Avalonia's
+					     runtime binding pipeline doesn't coerce string → FontFamily (the
+					     implicit conversion only fires at XAML parse time). The viewmodel
+					     projects Settings.SelectedFont through the right type and re-fires
+					     PropertyChanged when the picker selection changes. -->
 					<TextBlock Text="The quick brown fox jumps over the lazy dog"
-					           FontFamily="{Binding Settings.SelectedFont}"
+					           FontFamily="{Binding CurrentFontFamily}"
 					           FontSize="{Binding Settings.SelectedFontSize}" />
 				</Border>
 			</Grid>

ILSpy/Options/DisplaySettingsViewModel.cs

@@ -17,6 +17,7 @@
 // DEALINGS IN THE SOFTWARE.
 
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Xml.Linq;
 
@@ -47,9 +48,31 @@ namespace ILSpy.Options
 			.OrderBy(n => n, System.StringComparer.OrdinalIgnoreCase)
 			.ToArray();
 
-		public void Load(SettingsSnapshot snapshot)
+		/// <summary>
+		/// Derived FontFamily for the preview TextBlock. Avalonia's runtime binding pipeline
+		/// doesn't auto-coerce a <c>string</c> source to <see cref="FontFamily"/> (the implicit
+		/// conversion fires at XAML parse time, not on binding evaluation), so the preview
+		/// goes through this property — recomputed on every <see cref="DisplaySettings.SelectedFont"/>
+		/// change via the PropertyChanged subscription in <see cref="Load"/>.
+		/// </summary>
+		public FontFamily CurrentFontFamily =>
+			Settings != null && !string.IsNullOrEmpty(Settings.SelectedFont)
+				? new FontFamily(Settings.SelectedFont)
+				: FontFamily.Default;
+
+		public void Load(SettingsService service)
+		{
+			if (Settings != null)
+				Settings.PropertyChanged -= OnSettingsPropertyChanged;
+			Settings = service.DisplaySettings;
+			Settings.PropertyChanged += OnSettingsPropertyChanged;
+			OnPropertyChanged(nameof(CurrentFontFamily));
+		}
+
+		void OnSettingsPropertyChanged(object? sender, PropertyChangedEventArgs e)
 		{
-			Settings = snapshot.GetSettings<DisplaySettings>();
+			if (e.PropertyName == nameof(DisplaySettings.SelectedFont))
+				OnPropertyChanged(nameof(CurrentFontFamily));
 		}
 
 		public void LoadDefaults()

ILSpy/Options/IOptionPage.cs

@@ -21,14 +21,17 @@ namespace ILSpy.Options
 	/// <summary>
 	/// Plugin contract for individual panels in the Options tab. Each implementation is
 	/// MEF-discovered via <see cref="ExportOptionPageAttribute"/>; the host calls
-	/// <see cref="Load"/> with a snapshot of the current settings when the tab opens, and
-	/// <see cref="LoadDefaults"/> when the user clicks the per-panel reset button.
+	/// <see cref="Load"/> with the live settings service when the tab opens, and
+	/// <see cref="LoadDefaults"/> when the user clicks the per-panel reset button. Panels
+	/// bind directly to the live section instances — every toggle is immediately visible
+	/// to other consumers (the decompiler view, the tree, etc.). XML persistence rides on
+	/// <see cref="ILSpy.SettingsService.Save"/> at app exit.
 	/// </summary>
 	public interface IOptionPage
 	{
 		string Title { get; }
 
-		void Load(SettingsSnapshot settings);
+		void Load(SettingsService settings);
 
 		void LoadDefaults();
 	}

ILSpy/Options/MiscSettingsViewModel.cs

@@ -35,9 +35,9 @@ namespace ILSpy.Options
 		[ObservableProperty]
 		MiscSettings settings = null!;
 
-		public void Load(SettingsSnapshot snapshot)
+		public void Load(SettingsService service)
 		{
-			Settings = snapshot.GetSettings<MiscSettings>();
+			Settings = service.MiscSettings;
 		}
 
 		public void LoadDefaults()

ILSpy/Options/OptionsPageModel.cs

@@ -28,30 +28,31 @@ using ICSharpCode.ILSpy.Properties;
 namespace ILSpy.Options
 {
 	/// <summary>
-	/// Content viewmodel for the Options document tab. Wraps a <see cref="SettingsSnapshot"/>,
-	/// MEF-discovered <see cref="IOptionPage"/> panels (ordered by <see cref="IOptionsMetadata.Order"/>),
-	/// and the page-level Apply / Reset commands the panel views bind to.
+	/// Content viewmodel for the Options document tab. Wraps the live
+	/// <see cref="SettingsService"/>, MEF-discovered <see cref="IOptionPage"/> panels
+	/// (ordered by <see cref="IOptionsMetadata.Order"/>), and a Reset command that
+	/// rolls the currently-selected panel back to its built-in defaults.
+	/// <para>
+	/// Panels bind two-way to the live section instances, so every toggle takes effect
+	/// immediately — there's no Apply step. XML persistence rides on
+	/// <see cref="SettingsService.Save"/> at app exit.
+	/// </para>
 	/// </summary>
 	public sealed partial class OptionsPageModel : ObservableObject
 	{
-		readonly SettingsSnapshot snapshot;
-
 		public OptionsPageModel(SettingsService settingsService, IEnumerable<ExportFactory<IOptionPage, IOptionsMetadata>> pageFactories)
 		{
-			snapshot = settingsService.CreateSnapshot();
-
 			Pages = pageFactories
 				.OrderBy(f => f.Metadata.Order)
 				.Select(f => f.CreateExport().Value)
 				.ToArray();
 
 			foreach (var page in Pages)
-				page.Load(snapshot);
+				page.Load(settingsService);
 
 			selectedPage = Pages.FirstOrDefault();
 			Title = Resources._Options;
 
-			ApplyCommand = new RelayCommand(Apply);
 			ResetCurrentPageCommand = new RelayCommand(ResetCurrentPage);
 		}
 
@@ -67,12 +68,8 @@ namespace ILSpy.Options
 		[ObservableProperty]
 		IOptionPage? selectedPage;
 
-		public IRelayCommand ApplyCommand { get; }
-
 		public IRelayCommand ResetCurrentPageCommand { get; }
 
-		void Apply() => snapshot.Save();
-
 		void ResetCurrentPage() => SelectedPage?.LoadDefaults();
 	}
 }

ILSpy/Options/OptionsPageView.axaml

@@ -9,19 +9,17 @@
              x:Class="ILSpy.Options.OptionsPageView"
              x:DataType="vm:OptionsPageModel">
 	<DockPanel LastChildFill="True">
-		<!-- Apply / Reset live in the page footer rather than per-panel. Functionally
-		     identical to a per-panel Apply (every Apply commits the full snapshot);
-		     keeps the buttons accessible regardless of which inner tab is active and
-		     avoids parent-binding gymnastics from inside each panel's DataContext. -->
+		<!-- Reset rolls the currently-selected panel back to its built-in defaults.
+		     No Apply button — panel edits are live, applied immediately to the live
+		     SettingsService instances. XML persistence rides on app-exit Save. -->
 		<Border DockPanel.Dock="Bottom" BorderBrush="#FFC8CDD3" BorderThickness="0,1,0,0" Padding="8">
 			<StackPanel Orientation="Horizontal" HorizontalAlignment="Right" Spacing="6">
 				<Button Content="{x:Static res:Resources.ResetToDefaults}"
 				        Command="{Binding ResetCurrentPageCommand}" />
-				<Button Content="{x:Static res:Resources.OK}"
-				        Command="{Binding ApplyCommand}" />
 			</StackPanel>
 		</Border>
-		<TabControl ItemsSource="{Binding Pages}"
+		<TabControl TabStripPlacement="Left"
+		            ItemsSource="{Binding Pages}"
 		            SelectedItem="{Binding SelectedPage, Mode=TwoWay}">
 			<TabControl.ItemTemplate>
 				<DataTemplate x:DataType="vm:IOptionPage">

ILSpy/Options/SettingsSnapshot.cs

@@ -1,55 +0,0 @@
-// Copyright (c) 2026 AlphaSierraPapa for the SharpDevelop Team
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-using ICSharpCode.ILSpyX;
-using ICSharpCode.ILSpyX.Settings;
-
-namespace ILSpy.Options
-{
-	/// <summary>
-	/// In-memory copy of the persisted settings, used by the Options tab so panel edits
-	/// don't reach the live <see cref="ILSpy.SettingsService"/> until the user
-	/// clicks Apply. Inherits the standard <see cref="SettingsServiceBase.GetSettings{T}"/>
-	/// load+subscribe machinery from the shared base — sections materialise on first
-	/// access reading from the same XML root as the parent service, but are independent
-	/// object graphs. <see cref="Save"/> writes those graphs back through the parent's
-	/// <see cref="ISettingsProvider"/> and asks the parent to reload so subscribers see
-	/// the new values.
-	/// </summary>
-	public sealed class SettingsSnapshot : SettingsServiceBase
-	{
-		readonly SettingsService parent;
-
-		public SettingsSnapshot(SettingsService parent, ISettingsProvider spySettings) : base(spySettings)
-		{
-			this.parent = parent;
-		}
-
-		public void Save()
-		{
-			SpySettings.Update(root => {
-				foreach (var section in sections.Values)
-				{
-					SaveSection(section, root);
-				}
-			});
-
-			parent.Reload();
-		}
-	}
-}

ILSpy/SettingsService.cs

@@ -16,7 +16,6 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
-using System;
 using System.Composition;
 
 using ICSharpCode.ILSpyX;
@@ -45,34 +44,11 @@ namespace ILSpy
 		AssemblyListManager? assemblyListManager;
 		public AssemblyListManager AssemblyListManager => assemblyListManager ??= new(SpySettings);
 
-		/// <summary>Fired after <see cref="Reload"/> propagates fresh values from disk into the
-		/// live section instances. Subscribers (e.g. the assembly tree, the decompiler view)
-		/// observe this to refresh derived UI state.</summary>
-		public event EventHandler? SettingsChanged;
-
-		/// <summary>
-		/// Creates a parallel <see cref="SettingsSnapshot"/> bound to the same XML root. The
-		/// snapshot returns fresh, independent section instances on first access — Options
-		/// panels mutate those copies so the live service stays untouched until
-		/// <see cref="SettingsSnapshot.Save"/>.
-		/// </summary>
-		public SettingsSnapshot CreateSnapshot() => new(this, SpySettings);
-
 		/// <summary>
-		/// Reloads every materialised section from <see cref="SpySettings"/>. Called after a
-		/// snapshot commits so the live instances pick up the just-written values without
-		/// rebuilding the dictionary (subscribers see PropertyChanged for every changed field).
+		/// Persists every materialised section to disk. Options panels bind two-way to the
+		/// live instances so no in-memory commit is needed — <see cref="Save"/> just flushes
+		/// current state to XML. Called at app-exit from <c>App.axaml.cs</c>.
 		/// </summary>
-		public void Reload()
-		{
-			foreach (var section in sections.Values)
-			{
-				var element = SpySettings[section.SectionName];
-				section.LoadFromXml(element);
-			}
-			SettingsChanged?.Invoke(this, EventArgs.Empty);
-		}
-
 		public void Save()
 		{
 			SpySettings.Update(root => {