fix(sidebar): resolve MatchingService live + settings "סגור" label

Sidebar lookups threw ObjectDisposedException on the EspoCrmClient's
HttpClient after any settings save. TryInitializeCrm rebuilds the CRM
stack (new HttpClient + MatchingService) and disposes the old HttpClient,
but the long-lived sidebar ReadingPaneViewModel had captured the old
MatchingService and kept calling into the disposed client.

ReadingPaneViewModel now resolves the MatchingService live on each lookup
via a Func<IMatchingService?> provider (() => host.MatchingService), so
it always uses the current stack and degrades gracefully (shows "not
configured") when none exists. SidebarController no longer captures a
snapshot.

Also: rename the Settings dialog's bottom button from "ביטול" to "סגור".

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/OutlookAddin.UI/Dialogs/SettingsDialog.xaml

@@ -152,7 +152,7 @@
                     MinWidth="100" />
             <Button Command="{Binding CancelCommand}"
                     IsCancel="True"
-                    Content="ביטול"
+                    Content="סגור"
                     Padding="20,5"
                     MinWidth="100" />
         </StackPanel>

src/OutlookAddin.UI/ViewModels/FolderNodeViewModel.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Threading.Tasks;
+using System.Windows.Threading;
 using CommunityToolkit.Mvvm.ComponentModel;
 using MarcusLaw.OutlookAddin.Core.Services;
 using Serilog;
@@ -18,6 +19,7 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
     {
         private readonly IEspoCrmClient? _client;
         private readonly ILogger? _logger;
+        private readonly Dispatcher? _dispatcher;
         private bool _childrenLoaded;
         private bool _loadingStarted;
 
@@ -58,12 +60,14 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         public FolderNodeViewModel(
             IEspoCrmClient client,
             ILogger logger,
+            Dispatcher dispatcher,
             string name,
             string fullPath,
             string? relativePath)
         {
             _client = client ?? throw new ArgumentNullException(nameof(client));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
             Name = name;
             FullPath = fullPath;
             RelativePath = relativePath;
@@ -133,8 +137,15 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             }
             finally
             {
-                Children.Clear();
+                // Marshal onto the Dispatcher: once this node's TreeViewItem
-                foreach (var child in loaded) Children.Add(child);
+                // exists, Children is bound and must only be mutated on the UI
+                // thread (the network await above can resume on a thread-pool
+                // thread in this VSTO host).
+                OnUi(() =>
+                {
+                    Children.Clear();
+                    foreach (var child in loaded) Children.Add(child);
+                });
                 _childrenLoaded = true;
                 IsLoading = false;
             }
@@ -144,7 +155,14 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         {
             var fullPath = string.IsNullOrEmpty(FullPath) ? name : FullPath + "/" + name;
             var relativePath = IsRoot ? name : RelativePath + "/" + name;
-            return new FolderNodeViewModel(_client!, _logger!, name, fullPath, relativePath);
+            return new FolderNodeViewModel(_client!, _logger!, _dispatcher!, name, fullPath, relativePath);
+        }
+
+        private void OnUi(Action action)
+        {
+            var d = _dispatcher;
+            if (d == null || d.CheckAccess()) action();
+            else d.Invoke(action);
         }
     }
 }

src/OutlookAddin.UI/ViewModels/ReadingPaneViewModel.cs

@@ -27,7 +27,12 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
 
     public sealed partial class ReadingPaneViewModel : ObservableObject
     {
-        private readonly IMatchingService _matchingService;
+        // Resolved live on each lookup rather than captured once: the host
+        // rebuilds the CRM stack (new HttpClient + MatchingService) whenever
+        // settings are saved and disposes the old HttpClient. A captured
+        // snapshot would then call into a disposed HttpClient and throw
+        // ObjectDisposedException on every sidebar lookup.
+        private readonly Func<IMatchingService?> _matchingServiceProvider;
         private readonly ILogger _logger;
         private CancellationTokenSource? _activeLookup;
         // Stashes the ambiguous MatchResult while the user is drilling into
@@ -94,9 +99,9 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         /// </summary>
         public event EventHandler<string>? OpenInBrowserRequested;
 
-        public ReadingPaneViewModel(IMatchingService matchingService, ILogger logger)
+        public ReadingPaneViewModel(Func<IMatchingService?> matchingServiceProvider, ILogger logger)
         {
-            _matchingService = matchingService ?? throw new ArgumentNullException(nameof(matchingService));
+            _matchingServiceProvider = matchingServiceProvider ?? throw new ArgumentNullException(nameof(matchingServiceProvider));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
         }
 
@@ -162,12 +167,20 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             _ambiguousReturnTarget = null;
             State = ReadingPaneState.Loading;
 
+            var svc = _matchingServiceProvider();
+            if (svc == null)
+            {
+                ErrorMessage = "התוסף עדיין לא מוגדר. עדכן בהגדרות.";
+                State = ReadingPaneState.Error;
+                return;
+            }
+
             var cts = new CancellationTokenSource();
             _activeLookup = cts;
 
             try
             {
-                var result = await _matchingService.LookupAsync(senderEmail, cts.Token).ConfigureAwait(true);
+                var result = await svc.LookupAsync(senderEmail, cts.Token).ConfigureAwait(true);
                 if (cts.IsCancellationRequested) return;
 
                 if (result == null)
@@ -296,6 +309,14 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         {
             if (candidate == null || string.IsNullOrWhiteSpace(candidate.Id)) return;
 
+            var svc = _matchingServiceProvider();
+            if (svc == null)
+            {
+                ErrorMessage = "התוסף עדיין לא מוגדר. עדכן בהגדרות.";
+                State = ReadingPaneState.Error;
+                return;
+            }
+
             CancelInFlight();
             var cts = new CancellationTokenSource();
             _activeLookup = cts;
@@ -310,7 +331,7 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
 
             try
             {
-                var result = await _matchingService.LookupContactAsync(candidate.Id, rememberedEmail, cts.Token).ConfigureAwait(true);
+                var result = await svc.LookupContactAsync(candidate.Id, rememberedEmail, cts.Token).ConfigureAwait(true);
                 if (cts.IsCancellationRequested) return;
 
                 if (result == null || result.Contact == null)

src/OutlookAddin.UI/ViewModels/SaveAttachmentsViewModel.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Threading;
 using System.Threading.Tasks;
+using System.Windows.Threading;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
 using MarcusLaw.OutlookAddin.Core.Models;
@@ -31,6 +32,7 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
 
         private readonly IEspoCrmClient _client;
         private readonly ILogger _logger;
+        private readonly Dispatcher _dispatcher;
         private CancellationTokenSource? _searchCts;
 
         [ObservableProperty]
@@ -109,6 +111,13 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
         {
             _client = client ?? throw new ArgumentNullException(nameof(client));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            // Captured on the UI thread (the VM is constructed on the thread
+            // that shows the dialog). Used to marshal ObservableCollection
+            // mutations back onto the Dispatcher — in this VSTO host the WPF
+            // SynchronizationContext is not installed, so ConfigureAwait(true)
+            // resumes on a thread-pool thread and a bound-collection Add throws
+            // "changes ... from a thread different from the Dispatcher thread".
+            _dispatcher = Dispatcher.CurrentDispatcher;
 
             ResetFolderTree();
 
@@ -150,10 +159,20 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             }
         }
 
+        /// <summary>Runs <paramref name="action"/> on the UI/Dispatcher thread.</summary>
+        private void OnUi(Action action)
+        {
+            if (_dispatcher.CheckAccess()) action();
+            else _dispatcher.Invoke(action);
+        }
+
         private void ResetFolderTree()
         {
-            FolderTree.Clear();
+            OnUi(() =>
-            SelectedFolder = null;
+            {
+                FolderTree.Clear();
+                SelectedFolder = null;
+            });
         }
 
         partial void OnSearchTextChanged(string value)
@@ -234,10 +253,13 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             // default), expanded, and seeded with the default subfolders so
             // they appear even before the share listing returns. Deeper levels
             // load lazily as the user expands them.
-            var root = new FolderNodeViewModel(_client, _logger, RootSentinel, folderPath, relativePath: null);
+            var root = new FolderNodeViewModel(_client, _logger, _dispatcher, RootSentinel, folderPath, relativePath: null);
-            FolderTree.Add(root);
+            OnUi(() =>
-            SelectedFolder = root;
+            {
-            root.IsSelected = true;
+                FolderTree.Add(root);
+                SelectedFolder = root;
+                root.IsSelected = true;
+            });
 
             try
             {
@@ -247,7 +269,7 @@ namespace MarcusLaw.OutlookAddin.UI.ViewModels
             {
                 _logger.Warning(ex, "Listing subfolders for case {CaseId} failed", c.Id);
             }
-            root.IsExpanded = true;
+            OnUi(() => root.IsExpanded = true);
         }
 
         /// <summary>

src/OutlookAddin/Properties/AssemblyInfo.cs

@@ -33,6 +33,6 @@ using System.Security;
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion("1.2.15.0")]
+[assembly: AssemblyVersion("1.2.17.0")]
-[assembly: AssemblyFileVersion("1.2.15.0")]
+[assembly: AssemblyFileVersion("1.2.17.0")]
 

src/OutlookAddin/Services/AddInHost.cs

@@ -367,7 +367,6 @@ namespace OutlookAddin.Services
                 _sidebarController = new SidebarController(
                     taskPanes,
                     _outlookApp,
-                    MatchingService!,
                     this,
                     System.Windows.Threading.Dispatcher.CurrentDispatcher,
                     Logger);

src/OutlookAddin/Services/SidebarController.cs

@@ -27,7 +27,6 @@ namespace OutlookAddin.Services
 
         private readonly CustomTaskPaneCollection _taskPanes;
         private readonly Outlook.Application _app;
-        private readonly IMatchingService _matchingService;
         private readonly AddInHost _host;
         private readonly Dispatcher _dispatcher;
         private readonly ILogger _logger;
@@ -38,14 +37,12 @@ namespace OutlookAddin.Services
         public SidebarController(
             CustomTaskPaneCollection taskPanes,
             Outlook.Application app,
-            IMatchingService matchingService,
             AddInHost host,
             Dispatcher dispatcher,
             ILogger logger)
         {
             _taskPanes = taskPanes ?? throw new ArgumentNullException(nameof(taskPanes));
             _app = app ?? throw new ArgumentNullException(nameof(app));
-            _matchingService = matchingService ?? throw new ArgumentNullException(nameof(matchingService));
             _host = host ?? throw new ArgumentNullException(nameof(host));
             _dispatcher = dispatcher ?? throw new ArgumentNullException(nameof(dispatcher));
             _logger = logger ?? throw new ArgumentNullException(nameof(logger));
@@ -83,7 +80,7 @@ namespace OutlookAddin.Services
             if (_bindings.ContainsKey(key)) return;
 
             var view = new ReadingPaneView();
-            var vm = new ReadingPaneViewModel(_matchingService, _logger)
+            var vm = new ReadingPaneViewModel(() => _host.MatchingService, _logger)
             {
                 EspoCrmBaseUrl = _host.Settings.EspoCrmUrl
             };