CmdPal: Update Extension SDK classes to raise property change notifications only on change (#44547)

## Summary of the Pull Request

This PR introduces a new method  
`bool SetProperty<T>(ref T field, T value, [CallerMemberName] string?
propertyName = null)`
on `BaseObservable`.

The method updates the backing field only when the new value differs
from the current one and raises property change notifications only in
that case.

#### Summary

- Adds `SetProperty<T>` to `BaseObservable` to guard property change
notifications behind an actual value change.
- SDK API is not affected.
- Prevents unnecessary notifications from leaving the extension
boundary.
- Reduces redundant updates and saves a few round-trips between COM
objects and view models.
- Improves overall efficiency without changing observable behavior for
consumers.

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## PR Checklist

- [ ] Closes: #xxx
<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
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- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/BaseObservable.cs

@@ -2,6 +2,7 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Runtime.CompilerServices;
 using Windows.Foundation;
 
 namespace Microsoft.CommandPalette.Extensions.Toolkit;
@@ -14,7 +15,7 @@ public partial class BaseObservable : INotifyPropChanged
 {
     public event TypedEventHandler<object, IPropChangedEventArgs>? PropChanged;
 
-    protected void OnPropertyChanged(string propertyName)
+    protected void OnPropertyChanged([CallerMemberName] string? propertyName = null)
     {
         try
         {
@@ -22,10 +23,37 @@ public partial class BaseObservable : INotifyPropChanged
             // this can crash as we try to invoke the handlers from that process.
             // However, just catching it seems to still raise the event on the
             // new host?
-            PropChanged?.Invoke(this, new PropChangedEventArgs(propertyName));
+            PropChanged?.Invoke(this, new PropChangedEventArgs(propertyName!));
         }
         catch
         {
         }
     }
+
+    /// <summary>
+    /// Sets the backing field to the specified value and raises a property changed
+    /// notification if the value is different from the current one.
+    /// </summary>
+    /// <typeparam name="T">The type of the property.</typeparam>
+    /// <param name="field">A reference to the backing field for the property.</param>
+    /// <param name="value">The new value to assign to the property.</param>
+    /// <param name="propertyName">
+    /// The name of the property. This is optional and is usually supplied
+    /// automatically by the <see cref="CallerMemberNameAttribute"/>.
+    /// </param>
+    /// <returns>
+    /// <see langword="true"/> if the field was updated and a property changed
+    /// notification was raised; otherwise, <see langword="false"/>.
+    /// </returns>
+    protected bool SetProperty<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
+    {
+        if (EqualityComparer<T>.Default.Equals(field, value))
+        {
+            return false;
+        }
+
+        field = value;
+        OnPropertyChanged(propertyName!);
+        return true;
+    }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Command.cs

@@ -6,31 +6,11 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Command : BaseObservable, ICommand
 {
-    public virtual string Name
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Name));
-        }
-    }
-
-= string.Empty;
+    public virtual string Name { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public virtual string Id { get; set; } = string.Empty;
 
-    public virtual IconInfo Icon
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Icon));
-        }
-    }
-
-= new();
+    public virtual IconInfo Icon { get; set => SetProperty(ref field, value); } = new();
 
     IIconInfo ICommand.Icon => Icon;
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/CommandContextItem.cs

@@ -6,9 +6,9 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class CommandContextItem : CommandItem, ICommandContextItem
 {
-    public virtual bool IsCritical { get; set; }
+    public virtual bool IsCritical { get; set => SetProperty(ref field, value); }
 
-    public virtual KeyChord RequestedShortcut { get; set; }
+    public virtual KeyChord RequestedShortcut { get; set => SetProperty(ref field, value); }
 
     public CommandContextItem(ICommand command)
         : base(command)

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/CommandItem.cs

@@ -19,44 +19,36 @@ public partial class CommandItem : BaseObservable, ICommandItem, IExtendedAttrib
     private DataPackage? _dataPackage;
     private DataPackageView? _dataPackageView;
 
-    public virtual IIconInfo? Icon
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Icon));
-        }
-    }
+    public virtual IIconInfo? Icon { get; set => SetProperty(ref field, value); }
 
     public virtual string Title
     {
         get => !string.IsNullOrEmpty(_title) ? _title : _command?.Name ?? string.Empty;
-
         set
         {
+            var oldTitle = Title;
             _title = value;
-            OnPropertyChanged(nameof(Title));
+            if (Title != oldTitle)
+            {
+                OnPropertyChanged();
+            }
         }
     }
 
-    public virtual string Subtitle
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Subtitle));
-        }
-    }
-
-= string.Empty;
+    public virtual string Subtitle { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public virtual ICommand? Command
     {
         get => _command;
         set
         {
+            if (EqualityComparer<ICommand?>.Default.Equals(value, _command))
+            {
+                return;
+            }
+
+            var oldTitle = Title;
+
             if (_commandListener is not null)
             {
                 _commandListener.Detach();
@@ -71,8 +63,8 @@ public partial class CommandItem : BaseObservable, ICommandItem, IExtendedAttrib
                 value.PropChanged += _commandListener.OnEvent;
             }
 
-            OnPropertyChanged(nameof(Command));
-            if (string.IsNullOrEmpty(_title))
+            OnPropertyChanged();
+            if (string.IsNullOrEmpty(_title) && oldTitle != Title)
             {
                 OnPropertyChanged(nameof(Title));
             }
@@ -88,17 +80,7 @@ public partial class CommandItem : BaseObservable, ICommandItem, IExtendedAttrib
         }
     }
 
-    public virtual IContextItem[] MoreCommands
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(MoreCommands));
-        }
-    }
-
-= [];
+    public virtual IContextItem[] MoreCommands { get; set => SetProperty(ref field, value); } = [];
 
     public DataPackage? DataPackage
     {

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/CommandResult.cs

@@ -6,9 +6,9 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class CommandResult : ICommandResult
 {
-    public ICommandResultArgs? Args { get; private set; }
+    public ICommandResultArgs? Args { get; private init; }
 
-    public CommandResultKind Kind { get; private set; } = CommandResultKind.Dismiss;
+    public CommandResultKind Kind { get; private init; } = CommandResultKind.Dismiss;
 
     public static CommandResult Dismiss()
     {

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/ContentPage.cs

@@ -10,17 +10,9 @@ public abstract partial class ContentPage : Page, IContentPage
 {
     public event TypedEventHandler<object, IItemsChangedEventArgs>? ItemsChanged;
 
-    public virtual IDetails? Details
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Details));
-        }
-    }
+    public virtual IDetails? Details { get; set => SetProperty(ref field, value); }
 
-    public virtual IContextItem[] Commands { get; set; } = [];
+    public virtual IContextItem[] Commands { get; set => SetProperty(ref field, value); } = [];
 
     public abstract IContent[] GetContent();
 

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Details.cs

@@ -7,65 +7,15 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Details : BaseObservable, IDetails, IExtendedAttributesProvider
 {
-    public virtual IIconInfo HeroImage
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(HeroImage));
-        }
-    }
+    public virtual IIconInfo HeroImage { get; set => SetProperty(ref field, value); } = new IconInfo();
 
-= new IconInfo();
+    public virtual string Title { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual string Title
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Title));
-        }
-    }
+    public virtual string Body { get; set => SetProperty(ref field, value); } = string.Empty;
 
-= string.Empty;
+    public virtual IDetailsElement[] Metadata { get; set => SetProperty(ref field, value); } = [];
 
-    public virtual string Body
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Body));
-        }
-    }
-
-= string.Empty;
-
-    public virtual IDetailsElement[] Metadata
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Metadata));
-        }
-    }
-
-= [];
-
-    public virtual ContentSize Size
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Size));
-        }
-    }
-
-= ContentSize.Small;
+    public virtual ContentSize Size { get; set => SetProperty(ref field, value); } = ContentSize.Small;
 
     public IDictionary<string, object>? GetProperties() => new ValueSet()
     {

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Filter.cs

@@ -6,39 +6,9 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Filter : BaseObservable, IFilter
 {
-    public virtual IIconInfo Icon
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Icon));
-        }
-    }
+    public virtual IIconInfo Icon { get; set => SetProperty(ref field, value); } = new IconInfo();
 
-= new IconInfo();
+    public virtual string Id { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual string Id
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Id));
-        }
-    }
-
-= string.Empty;
-
-    public virtual string Name
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Name));
-        }
-    }
-
-= string.Empty;
+    public virtual string Name { get; set => SetProperty(ref field, value); } = string.Empty;
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Filters.cs

@@ -6,17 +6,7 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public abstract partial class Filters : BaseObservable, IFilters
 {
-    public string CurrentFilterId
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(CurrentFilterId));
-        }
-    }
-
-    = string.Empty;
+    public string CurrentFilterId { get; set => SetProperty(ref field, value); } = string.Empty;
 
     // This method should be overridden in derived classes to provide the actual filters.
     public abstract IFilterItem[] GetFilters();

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/FormContent.cs

@@ -6,41 +6,11 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class FormContent : BaseObservable, IFormContent
 {
-    public virtual string DataJson
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(DataJson));
-        }
-    }
+    public virtual string DataJson { get; set => SetProperty(ref field, value); } = string.Empty;
 
-= string.Empty;
+    public virtual string StateJson { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual string StateJson
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(StateJson));
-        }
-    }
-
-= string.Empty;
-
-    public virtual string TemplateJson
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(TemplateJson));
-        }
-    }
-
-= string.Empty;
+    public virtual string TemplateJson { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public virtual ICommandResult SubmitForm(string inputs, string data) => SubmitForm(inputs);
 

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/GalleryGridLayout.cs

@@ -6,27 +6,7 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class GalleryGridLayout : BaseObservable, IGalleryGridLayout
 {
-    public virtual bool ShowTitle
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(ShowTitle));
-        }
-    }
+    public virtual bool ShowTitle { get; set => SetProperty(ref field, value); } = true;
 
-    = true;
-
-    public virtual bool ShowSubtitle
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(ShowSubtitle));
-        }
-    }
-
-    = true;
+    public virtual bool ShowSubtitle { get; set => SetProperty(ref field, value); } = true;
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/IconData.cs

@@ -2,7 +2,6 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System.Diagnostics.CodeAnalysis;
 using Windows.Storage.Streams;
 
 namespace Microsoft.CommandPalette.Extensions.Toolkit;

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/ListItem.cs

@@ -6,51 +6,13 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class ListItem : CommandItem, IListItem
 {
-    private ITag[] _tags = [];
-    private IDetails? _details;
+    public virtual ITag[] Tags { get; set => SetProperty(ref field, value); } = [];
 
-    private string _section = string.Empty;
-    private string _textToSuggest = string.Empty;
+    public virtual IDetails? Details { get; set => SetProperty(ref field, value); }
 
-    public virtual ITag[] Tags
-    {
-        get => _tags;
-        set
-        {
-            _tags = value;
-            OnPropertyChanged(nameof(Tags));
-        }
-    }
+    public virtual string Section { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual IDetails? Details
-    {
-        get => _details;
-        set
-        {
-            _details = value;
-            OnPropertyChanged(nameof(Details));
-        }
-    }
-
-    public virtual string Section
-    {
-        get => _section;
-        set
-        {
-            _section = value;
-            OnPropertyChanged(nameof(Section));
-        }
-    }
-
-    public virtual string TextToSuggest
-    {
-        get => _textToSuggest;
-        set
-        {
-            _textToSuggest = value;
-            OnPropertyChanged(nameof(TextToSuggest));
-        }
-    }
+    public virtual string TextToSuggest { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public ListItem(ICommand command)
         : base(command)

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/ListPage.cs

@@ -8,85 +8,23 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class ListPage : Page, IListPage
 {
-    private string _placeholderText = string.Empty;
-    private string _searchText = string.Empty;
-    private bool _showDetails;
-    private bool _hasMore;
-    private IFilters? _filters;
-    private IGridProperties? _gridProperties;
-    private ICommandItem? _emptyContent;
-
     public event TypedEventHandler<object, IItemsChangedEventArgs>? ItemsChanged;
 
-    public virtual string PlaceholderText
-    {
-        get => _placeholderText;
-        set
-        {
-            _placeholderText = value;
-            OnPropertyChanged(nameof(PlaceholderText));
-        }
-    }
+    private string _searchText = string.Empty;
 
-    public virtual string SearchText
-    {
-        get => _searchText;
-        set
-        {
-            _searchText = value;
-            OnPropertyChanged(nameof(SearchText));
-        }
-    }
+    public virtual string PlaceholderText { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual bool ShowDetails
-    {
-        get => _showDetails;
-        set
-        {
-            _showDetails = value;
-            OnPropertyChanged(nameof(ShowDetails));
-        }
-    }
+    public virtual string SearchText { get => _searchText; set => SetProperty(ref _searchText, value); }
 
-    public virtual bool HasMoreItems
-    {
-        get => _hasMore;
-        set
-        {
-            _hasMore = value;
-            OnPropertyChanged(nameof(HasMoreItems));
-        }
-    }
+    public virtual bool ShowDetails { get; set => SetProperty(ref field, value); }
 
-    public virtual IFilters? Filters
-    {
-        get => _filters;
-        set
-        {
-            _filters = value;
-            OnPropertyChanged(nameof(Filters));
-        }
-    }
+    public virtual bool HasMoreItems { get; set => SetProperty(ref field, value); }
 
-    public virtual IGridProperties? GridProperties
-    {
-        get => _gridProperties;
-        set
-        {
-            _gridProperties = value;
-            OnPropertyChanged(nameof(GridProperties));
-        }
-    }
+    public virtual IFilters? Filters { get; set => SetProperty(ref field, value); }
 
-    public virtual ICommandItem? EmptyContent
-    {
-        get => _emptyContent;
-        set
-        {
-            _emptyContent = value;
-            OnPropertyChanged(nameof(EmptyContent));
-        }
-    }
+    public virtual IGridProperties? GridProperties { get; set => SetProperty(ref field, value); }
+
+    public virtual ICommandItem? EmptyContent { get; set => SetProperty(ref field, value); }
 
     public virtual IListItem[] GetItems() => [];
 

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/MarkdownContent.cs

@@ -6,17 +6,7 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class MarkdownContent : BaseObservable, IMarkdownContent
 {
-    public virtual string Body
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Body));
-        }
-    }
-
-= string.Empty;
+    public virtual string Body { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public MarkdownContent()
     {

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/MediumGridLayout.cs

@@ -6,15 +6,5 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class MediumGridLayout : BaseObservable, IMediumGridLayout
 {
-    public virtual bool ShowTitle
-    {
-        get => field;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(ShowTitle));
-        }
-    }
-
-    = true;
+    public virtual bool ShowTitle { get; set => SetProperty(ref field, value); } = true;
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Page.cs

@@ -6,37 +6,9 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Page : Command, IPage
 {
-    private bool _loading;
-    private string _title = string.Empty;
-    private OptionalColor _accentColor;
+    public virtual bool IsLoading { get; set => SetProperty(ref field, value); }
 
-    public virtual bool IsLoading
-    {
-        get => _loading;
-        set
-        {
-            _loading = value;
-            OnPropertyChanged(nameof(IsLoading));
-        }
-    }
+    public virtual string Title { get; set => SetProperty(ref field, value); } = string.Empty;
 
-    public virtual string Title
-    {
-        get => _title;
-        set
-        {
-            _title = value;
-            OnPropertyChanged(nameof(Title));
-        }
-    }
-
-    public virtual OptionalColor AccentColor
-    {
-        get => _accentColor;
-        set
-        {
-            _accentColor = value;
-            OnPropertyChanged(nameof(AccentColor));
-        }
-    }
+    public virtual OptionalColor AccentColor { get; set => SetProperty(ref field, value); }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/ProgressState.cs

@@ -6,27 +6,7 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class ProgressState : BaseObservable, IProgressState
 {
-    private bool _isIndeterminate;
+    public virtual bool IsIndeterminate { get; set => SetProperty(ref field, value); }
 
-    private uint _progressPercent;
-
-    public virtual bool IsIndeterminate
-    {
-        get => _isIndeterminate;
-        set
-        {
-            _isIndeterminate = value;
-            OnPropertyChanged(nameof(IsIndeterminate));
-        }
-    }
-
-    public virtual uint ProgressPercent
-    {
-        get => _progressPercent;
-        set
-        {
-            _progressPercent = value;
-            OnPropertyChanged(nameof(ProgressPercent));
-        }
-    }
+    public virtual uint ProgressPercent { get; set => SetProperty(ref field, value); }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/PropChangedEventArgs.cs

@@ -2,8 +2,6 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using Windows.Foundation;
-
 namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class PropChangedEventArgs : IPropChangedEventArgs

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Section.cs

@@ -12,11 +12,6 @@ public sealed partial class Section : IEnumerable<IListItem>
 
     public string SectionTitle { get; set; } = string.Empty;
 
-    private Separator CreateSectionListItem()
-    {
-        return new Separator(SectionTitle);
-    }
-
     public Section(string sectionName, IListItem[] items)
     {
         SectionTitle = sectionName;
@@ -33,6 +28,11 @@ public sealed partial class Section : IEnumerable<IListItem>
     {
     }
 
+    private Separator CreateSectionListItem()
+    {
+        return new Separator(SectionTitle);
+    }
+
     public IEnumerator<IListItem> GetEnumerator() => Items.ToList().GetEnumerator();
 
     IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Separator.cs

@@ -4,15 +4,8 @@
 
 namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
-public partial class Separator : IListItem, ISeparatorContextItem, ISeparatorFilterItem
+public partial class Separator : BaseObservable, IListItem, ISeparatorContextItem, ISeparatorFilterItem
 {
-    public Separator(string? title = "")
-        : base()
-    {
-        Section = title ?? string.Empty;
-        Command = null;
-    }
-
     public IDetails? Details => null;
 
     public string? Section { get; private set; }
@@ -21,7 +14,7 @@ public partial class Separator : IListItem, ISeparatorContextItem, ISeparatorFil
 
     public string? TextToSuggest => null;
 
-    public ICommand? Command { get; private set; }
+    public ICommand? Command => null;
 
     public IIconInfo? Icon => null;
 
@@ -32,12 +25,19 @@ public partial class Separator : IListItem, ISeparatorContextItem, ISeparatorFil
     public string? Title
     {
         get => Section;
-        set => Section = value;
+        set
+        {
+            if (Section != value)
+            {
+                Section = value;
+                OnPropertyChanged();
+                OnPropertyChanged(Section);
+            }
+        }
     }
 
-    public event Windows.Foundation.TypedEventHandler<object, IPropChangedEventArgs>? PropChanged
+    public Separator(string? title = "")
     {
-        add { }
-        remove { }
+        Section = title ?? string.Empty;
     }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/StatusMessage.cs

@@ -6,37 +6,9 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class StatusMessage : BaseObservable, IStatusMessage
 {
-    public virtual string Message
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Message));
-        }
-    }
+    public virtual string Message { get; set => SetProperty(ref field, value); } = string.Empty;
 
-= string.Empty;
+    public virtual MessageState State { get; set => SetProperty(ref field, value); } = MessageState.Info;
 
-    public virtual MessageState State
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(State));
-        }
-    }
-
-= MessageState.Info;
-
-    public virtual IProgressState? Progress
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Progress));
-        }
-    }
+    public virtual IProgressState? Progress { get; set => SetProperty(ref field, value); }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/Tag.cs

@@ -6,63 +6,15 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class Tag : BaseObservable, ITag
 {
-    private OptionalColor _foreground;
-    private OptionalColor _background;
-    private string _text = string.Empty;
+    public virtual OptionalColor Foreground { get; set => SetProperty(ref field, value); }
 
-    public virtual OptionalColor Foreground
-    {
-        get => _foreground;
-        set
-        {
-            _foreground = value;
-            OnPropertyChanged(nameof(Foreground));
-        }
-    }
+    public virtual OptionalColor Background { get; set => SetProperty(ref field, value); }
 
-    public virtual OptionalColor Background
-    {
-        get => _background;
-        set
-        {
-            _background = value;
-            OnPropertyChanged(nameof(Background));
-        }
-    }
+    public virtual IIconInfo Icon { get; set => SetProperty(ref field, value); } = new IconInfo();
 
-    public virtual IIconInfo Icon
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(Icon));
-        }
-    }
+    public virtual string Text { get; set => SetProperty(ref field, value); } = string.Empty;
 
-= new IconInfo();
-
-    public virtual string Text
-    {
-        get => _text;
-        set
-        {
-            _text = value;
-            OnPropertyChanged(nameof(Text));
-        }
-    }
-
-    public virtual string ToolTip
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(ToolTip));
-        }
-    }
-
-= string.Empty;
+    public virtual string ToolTip { get; set => SetProperty(ref field, value); } = string.Empty;
 
     public Tag()
     {
@@ -70,6 +22,6 @@ public partial class Tag : BaseObservable, ITag
 
     public Tag(string text)
     {
-        _text = text;
+        Text = text;
     }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/TreeContent.cs

@@ -8,19 +8,11 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
 public partial class TreeContent : BaseObservable, ITreeContent
 {
+    public event TypedEventHandler<object, IItemsChangedEventArgs>? ItemsChanged;
+
     public IContent[] Children { get; set; } = [];
 
-    public virtual IContent? RootContent
-    {
-        get;
-        set
-        {
-            field = value;
-            OnPropertyChanged(nameof(RootContent));
-        }
-    }
-
-    public event TypedEventHandler<object, IItemsChangedEventArgs>? ItemsChanged;
+    public virtual IContent? RootContent { get; set => SetProperty(ref field, value); }
 
     public virtual IContent[] GetChildren() => Children;