New WinoListView implementation with multiple selections.

Wino.Mail.ViewModels/Collections/GroupedEmailCollection.cs

@@ -1180,7 +1180,7 @@ public partial class GroupedEmailCollection : ObservableObject, IRecipient<Prope
         foreach (var expander in _threadExpanders.Values)
         {
             expander.IsSelected = false;
-            
+
             // Also explicitly deselect individual emails within threads
             foreach (var threadEmail in expander.ThreadEmails)
             {
@@ -1363,7 +1363,7 @@ public partial class GroupedEmailCollection : ObservableObject, IRecipient<Prope
         return item switch
         {
             MailItemViewModel email => email.MailCopy?.CreationDate ?? DateTime.MinValue,
-            ThreadMailItemViewModel expander => expander.LatestEmailDate,
+            ThreadMailItemViewModel expander => expander.LatestMailViewModel?.CreationDate ?? DateTime.MinValue,
             _ => DateTime.MinValue
         };
     }

Wino.Mail.ViewModels/Collections/WinoMailCollection.cs

@@ -3,15 +3,19 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.Collections;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Messaging;
+using MoreLinq.Extensions;
 using Serilog;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Mail.ViewModels.Data;
+using Wino.Messaging.Client.Mails;
 
 namespace Wino.Mail.ViewModels.Collections;
 
-public class WinoMailCollection
+public class WinoMailCollection : ObservableRecipient, IRecipient<SelectedItemsChangedMessage>
 {
     // We cache each mail copy id for faster access on updates.
     // If the item provider here for update or removal doesn't exist here
@@ -20,6 +24,7 @@ public class WinoMailCollection
     public HashSet<Guid> MailCopyIdHashSet = [];
 
     public event EventHandler<MailItemViewModel> MailItemRemoved;
+    public event EventHandler ItemSelectionChanged;
 
     private ListItemComparer listComparer = new();
 
@@ -32,6 +37,16 @@ public class WinoMailCollection
     /// </summary>
     public SortingOptionType SortingType { get; set; }
 
+    /// <summary>
+    /// Gets or sets the grouping type for emails.
+    /// Note: WinoMailCollection groups automatically on the UI, so this just affects the grouping key logic.
+    /// </summary>
+    public EmailGroupingType GroupingType
+    {
+        get => SortingType == SortingOptionType.ReceiveDate ? EmailGroupingType.ByDate : EmailGroupingType.ByFromName;
+        set => SortingType = value == EmailGroupingType.ByDate ? SortingOptionType.ReceiveDate : SortingOptionType.Sender;
+    }
+
     /// <summary>
     /// Automatically deletes single mail items after the delete operation or thread->single transition.
     /// This is useful when reply draft is discarded in the thread. Only enabled for Draft folder for now.
@@ -40,14 +55,31 @@ public class WinoMailCollection
 
     public int Count => _mailItemSource.Count;
 
+    public bool IsAllSelected
+    {
+        get
+        {
+            return AllItemsCount == SelectedItemsCount;
+        }
+    }
+
     public IDispatcher CoreDispatcher { get; set; }
 
     public WinoMailCollection()
     {
         MailItems = new ReadOnlyObservableGroupedCollection<object, IMailListItem>(_mailItemSource);
+
+        Messenger.Register<SelectedItemsChangedMessage>(this);
     }
 
-    public void Clear() => _mailItemSource.Clear();
+    public async Task ClearAsync()
+    {
+        await ExecuteUIThread(() =>
+        {
+            _mailItemSource.Clear();
+            MailCopyIdHashSet.Clear();
+        });
+    }
 
     private object GetGroupingKey(IMailListItem mailItem)
     {
@@ -72,13 +104,16 @@ public class WinoMailCollection
         }
     }
 
-    private void InsertItemInternal(object groupKey, IMailListItem mailItem)
+    private async Task InsertItemInternalAsync(object groupKey, IMailListItem mailItem)
     {
         UpdateUniqueIdHashes(mailItem, true);
-        _mailItemSource.InsertItem(groupKey, listComparer, mailItem, listComparer);
+        await ExecuteUIThread(() =>
+        {
+            _mailItemSource.InsertItem(groupKey, listComparer, mailItem, listComparer);
+        });
     }
 
-    private void RemoveItemInternal(ObservableGroup<object, IMailListItem> group, IMailListItem mailItem)
+    private async Task RemoveItemInternalAsync(ObservableGroup<object, IMailListItem> group, IMailListItem mailItem)
     {
         UpdateUniqueIdHashes(mailItem, false);
 
@@ -94,12 +129,15 @@ public class WinoMailCollection
             }
         }
 
-        group.Remove(mailItem);
-
-        if (group.Count == 0)
+        await ExecuteUIThread(() =>
         {
-            _mailItemSource.RemoveGroup(group.Key);
-        }
+            group.Remove(mailItem);
+
+            if (group.Count == 0)
+            {
+                _mailItemSource.RemoveGroup(group.Key);
+            }
+        });
     }
 
     private async Task HandleThreadingAsync(ObservableGroup<object, IMailListItem> group, IMailListItem item, MailCopy addedItem)
@@ -118,8 +156,8 @@ public class WinoMailCollection
     {
         var existingGroupKey = GetGroupingKey(threadViewModel);
 
-        await ExecuteUIThread(() => 
-        { 
+        await ExecuteUIThread(() =>
+        {
             var newMailItem = new MailItemViewModel(addedItem);
             threadViewModel.AddEmail(newMailItem);
         });
@@ -152,17 +190,14 @@ public class WinoMailCollection
 
     private async Task MoveThreadToNewGroupAsync(ObservableGroup<object, IMailListItem> currentGroup, ThreadMailItemViewModel threadViewModel, object newGroupKey)
     {
-        await ExecuteUIThread(() =>
-        {
-            RemoveItemInternal(currentGroup, threadViewModel);
-            InsertItemInternal(newGroupKey, threadViewModel);
-        });
+        await RemoveItemInternalAsync(currentGroup, threadViewModel);
+        await InsertItemInternalAsync(newGroupKey, threadViewModel);
     }
 
     private async Task CreateNewThreadAsync(ObservableGroup<object, IMailListItem> group, MailItemViewModel item, MailCopy addedItem)
     {
         var threadViewModel = new ThreadMailItemViewModel(item.MailCopy.ThreadId);
-        
+
         await ExecuteUIThread(() =>
         {
             threadViewModel.AddEmail(item);
@@ -171,11 +206,8 @@ public class WinoMailCollection
 
         var newGroupKey = GetGroupingKey(threadViewModel);
 
-        await ExecuteUIThread(() =>
-        {
-            RemoveItemInternal(group, item);
-            InsertItemInternal(newGroupKey, threadViewModel);
-        });
+        await RemoveItemInternalAsync(group, item);
+        await InsertItemInternalAsync(newGroupKey, threadViewModel);
     }
 
     public async Task AddAsync(MailCopy addedItem)
@@ -185,8 +217,8 @@ public class WinoMailCollection
             foreach (var item in group)
             {
                 // Compare ThreadIds - if they match and both have ThreadIds, thread them together
-                bool shouldThread = !string.IsNullOrEmpty(addedItem.ThreadId) && 
-                                  item is MailItemViewModel mailItem && 
+                bool shouldThread = !string.IsNullOrEmpty(addedItem.ThreadId) &&
+                                  item is MailItemViewModel mailItem &&
                                   !string.IsNullOrEmpty(mailItem.MailCopy.ThreadId) &&
                                   string.Equals(addedItem.ThreadId, mailItem.MailCopy.ThreadId, StringComparison.OrdinalIgnoreCase);
 
@@ -194,7 +226,7 @@ public class WinoMailCollection
                 {
                     // Check if any email in the thread has matching ThreadId
                     shouldThread = !string.IsNullOrEmpty(addedItem.ThreadId) &&
-                                 threadViewModel.ThreadEmails.Any(e => 
+                                 threadViewModel.ThreadEmails.Any(e =>
                                      !string.IsNullOrEmpty(e.MailCopy.ThreadId) &&
                                      string.Equals(addedItem.ThreadId, e.MailCopy.ThreadId, StringComparison.OrdinalIgnoreCase));
                 }
@@ -219,7 +251,7 @@ public class WinoMailCollection
     {
         var newMailItem = new MailItemViewModel(addedItem);
         var groupKey = GetGroupingKey(newMailItem);
-        await ExecuteUIThread(() => { InsertItemInternal(groupKey, newMailItem); });
+        await InsertItemInternalAsync(groupKey, newMailItem);
     }
 
     private async Task UpdateExistingItemAsync(MailItemViewModel existingItem, MailCopy updatedItem)
@@ -230,7 +262,10 @@ public class WinoMailCollection
         await ExecuteUIThread(() => { existingItem.MailCopy = updatedItem; });
     }
 
-    public void AddRange(IEnumerable<IMailListItem> items, bool clearIdCache)
+    /// <summary>
+    /// Adds multiple emails to the collection.
+    /// </summary>
+    public async Task AddRangeAsync(IEnumerable<IMailListItem> items, bool clearIdCache)
     {
         if (clearIdCache)
         {
@@ -238,31 +273,34 @@ public class WinoMailCollection
         }
 
         var groupedByName = items
-                            .GroupBy(a => GetGroupingKey(a))
+                            .GroupBy(GetGroupingKey)
                             .Select(a => new ObservableGroup<object, IMailListItem>(a.Key, a));
 
-        foreach (var group in groupedByName)
+        await ExecuteUIThread(() =>
         {
-            // Store all mail copy ids for faster access.
-            foreach (var item in group)
-            {
-                UpdateUniqueIdHashes(item, true);
-            }
-
-            var existingGroup = _mailItemSource.FirstGroupByKeyOrDefault(group.Key);
-
-            if (existingGroup == null)
-            {
-                _mailItemSource.AddGroup(group.Key, group);
-            }
-            else
+            foreach (var group in groupedByName)
             {
+                // Store all mail copy ids for faster access.
                 foreach (var item in group)
                 {
-                    existingGroup.Add(item);
+                    UpdateUniqueIdHashes(item, true);
+                }
+
+                var existingGroup = _mailItemSource.FirstGroupByKeyOrDefault(group.Key);
+
+                if (existingGroup == null)
+                {
+                    _mailItemSource.AddGroup(group.Key, group);
+                }
+                else
+                {
+                    foreach (var item in group)
+                    {
+                        existingGroup.Add(item);
+                    }
                 }
             }
-        }
+        });
     }
 
     public MailItemContainer GetMailItemContainer(Guid uniqueMailId)
@@ -291,17 +329,20 @@ public class WinoMailCollection
         return null;
     }
 
-    public void UpdateThumbnails(string address)
+    /// <summary>
+    /// Updates thumbnails for all mail items with the specified address.
+    /// </summary>
+    public Task UpdateThumbnailsForAddressAsync(string address)
     {
-        if (CoreDispatcher == null) return;
+        if (CoreDispatcher == null) return Task.CompletedTask;
 
-        CoreDispatcher.ExecuteOnUIThread(() =>
+        return CoreDispatcher.ExecuteOnUIThread(() =>
         {
             foreach (var group in _mailItemSource)
             {
                 foreach (var item in group)
                 {
-                    if (item is MailItemViewModel mailItemViewModel && mailItemViewModel.MailCopy.FromAddress.Equals(address, StringComparison.OrdinalIgnoreCase))
+                    if (item is MailItemViewModel mailItemViewModel && mailItemViewModel.MailCopy.FromAddress?.Equals(address, StringComparison.OrdinalIgnoreCase) == true)
                     {
                         mailItemViewModel.ThumbnailUpdatedEvent = !mailItemViewModel.ThumbnailUpdatedEvent;
                     }
@@ -309,7 +350,7 @@ public class WinoMailCollection
                     {
                         foreach (var threadMailItem in threadViewModel.ThreadEmails)
                         {
-                            if (threadMailItem.MailCopy.FromAddress.Equals(address, StringComparison.OrdinalIgnoreCase))
+                            if (threadMailItem.MailCopy.FromAddress?.Equals(address, StringComparison.OrdinalIgnoreCase) == true)
                             {
                                 threadMailItem.ThumbnailUpdatedEvent = !threadMailItem.ThumbnailUpdatedEvent;
                             }
@@ -325,15 +366,12 @@ public class WinoMailCollection
     /// </summary>
     /// <param name="updatedMailCopy">Updated mail copy.</param>
     /// <returns></returns>
-    public async Task UpdateMailCopy(MailCopy updatedMailCopy)
+    public Task UpdateMailCopy(MailCopy updatedMailCopy)
     {
         // This item doesn't exist in the list.
-        if (!MailCopyIdHashSet.Contains(updatedMailCopy.UniqueId))
-        {
-            return;
-        }
+        if (!MailCopyIdHashSet.Contains(updatedMailCopy.UniqueId)) return Task.CompletedTask;
 
-        await ExecuteUIThread(() =>
+        return ExecuteUIThread(() =>
         {
             var itemContainer = GetMailItemContainer(updatedMailCopy.UniqueId);
 
@@ -356,6 +394,8 @@ public class WinoMailCollection
         });
     }
 
+    public MailItemViewModel GetFirst() => AllItems.ElementAtOrDefault(0);
+
     public MailItemViewModel GetNextItem(MailCopy mailCopy)
     {
         try
@@ -466,11 +506,8 @@ public class WinoMailCollection
                         var singleViewModel = threadMailItemViewModel.ThreadEmails.First();
                         var groupKey = GetGroupingKey(singleViewModel);
 
-                        await ExecuteUIThread(() =>
-                        {
-                            RemoveItemInternal(group, threadMailItemViewModel);
-                            InsertItemInternal(groupKey, singleViewModel);
-                        });
+                        await RemoveItemInternalAsync(group, threadMailItemViewModel);
+                        await InsertItemInternalAsync(groupKey, singleViewModel);
 
                         // If thread->single conversion is being done, we should ignore it for non-draft items.
                         // eg. Deleting a reply message from draft folder. Single non-draft item should not be re-added.
@@ -483,13 +520,13 @@ public class WinoMailCollection
 
                             if (newGroup != null)
                             {
-                                await ExecuteUIThread(() => { RemoveItemInternal(newGroup, singleViewModel); });
+                                await RemoveItemInternalAsync(newGroup, singleViewModel);
                             }
                         }
                     }
                     else if (threadMailItemViewModel.EmailCount == 0)
                     {
-                        await ExecuteUIThread(() => { RemoveItemInternal(group, threadMailItemViewModel); });
+                        await RemoveItemInternalAsync(group, threadMailItemViewModel);
                     }
                     else
                     {
@@ -502,7 +539,7 @@ public class WinoMailCollection
                 }
                 else if (item is MailItemViewModel mailItemViewModel && mailItemViewModel.MailCopy.UniqueId == removeItem.UniqueId)
                 {
-                    await ExecuteUIThread(() => { RemoveItemInternal(group, item); });
+                    await RemoveItemInternalAsync(group, item);
 
                     shouldExit = true;
 
@@ -510,7 +547,120 @@ public class WinoMailCollection
                 }
             }
         }
+
+        await NotifySelectionChangesAsync();
     }
 
+    private IEnumerable<MailItemViewModel> AllItems
+    {
+        get
+        {
+            foreach (var group in _mailItemSource)
+            {
+                foreach (var item in group)
+                {
+                    if (item is not MailItemViewModel mailItemViewModel) throw new Exception("Item is not MailItemViewModel in AllItems");
+
+                    if (item is ThreadMailItemViewModel threadMail)
+                    {
+                        foreach (var singleItem in threadMail.ThreadEmails)
+                        {
+                            yield return singleItem;
+                        }
+                    }
+
+                    yield return mailItemViewModel;
+                }
+            }
+        }
+    }
+
+    public IEnumerable<MailItemViewModel> SelectedItems => AllItems.Where(a => a.IsSelected);
+    public int SelectedItemsCount => AllItems.Count(a => a.IsSelected);
+    public int AllItemsCount => AllItems.Count();
+    public bool IsAllItemsSelected => AllItems.Any() && AllItems.All(a => a.IsSelected);
+    public bool HasSingleItemSelected => SelectedItemsCount == 1;
+
+    public async Task ExecuteWithoutRaiseSelectionChangedAsync(Action<MailItemViewModel> action)
+    {
+        try
+        {
+            // Do not listen to individual selection changes while we are doing bulk selection.
+            Messenger.Unregister<SelectedItemsChangedMessage>(this);
+
+            await ExecuteUIThread(() =>
+            {
+                foreach (var item in AllItems)
+                {
+                    action(item);
+                }
+            });
+        }
+        catch (Exception)
+        {
+        }
+        finally
+        {
+            Messenger.Register<SelectedItemsChangedMessage>(this);
+            Messenger.Send(new SelectedItemsChangedMessage());
+
+            await NotifySelectionChangesAsync();
+        }
+    }
+
+    public Task ToggleSelectAllAsync()
+    {
+        if (IsAllItemsSelected)
+        {
+            return UnselectAllAsync();
+        }
+        else
+        {
+            return SelectAllAsync();
+        }
+    }
+
+    /// <summary>
+    /// Gets the index of an item in the flat Items collection.
+    /// Note: WinoMailCollection doesn't have a flat Items collection like GroupedEmailCollection.
+    /// This returns -1 as it's not applicable to the grouped structure.
+    /// </summary>
+    public int IndexOf(object item)
+    {
+        // WinoMailCollection uses grouped structure, so we need to search through groups
+        int currentIndex = 0;
+
+        foreach (var group in _mailItemSource)
+        {
+            foreach (var groupItem in group)
+            {
+                if (ReferenceEquals(groupItem, item))
+                {
+                    return currentIndex;
+                }
+                currentIndex++;
+            }
+        }
+
+        return -1;
+    }
+
+    public Task SelectAllAsync() => ExecuteWithoutRaiseSelectionChangedAsync(a => a.IsSelected = true);
+    public Task UnselectAllAsync() => ExecuteWithoutRaiseSelectionChangedAsync(a => a.IsSelected = false);
+
     private async Task ExecuteUIThread(Action action) => await CoreDispatcher?.ExecuteOnUIThread(action);
+
+    public void Receive(SelectedItemsChangedMessage message) => _ = NotifySelectionChangesAsync();
+
+    private async Task NotifySelectionChangesAsync()
+    {
+        await ExecuteUIThread(() =>
+        {
+            OnPropertyChanged(nameof(IsAllItemsSelected));
+            OnPropertyChanged(nameof(SelectedItemsCount));
+            OnPropertyChanged(nameof(HasSingleItemSelected));
+
+            ItemSelectionChanged?.Invoke(this, null);
+        });
+    }
 }

Wino.Mail.ViewModels/Data/IMailListItem.cs

@@ -1,4 +1,6 @@
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
 using Wino.Core.Domain.Interfaces;
 
 namespace Wino.Mail.ViewModels.Data;
@@ -7,7 +9,7 @@ namespace Wino.Mail.ViewModels.Data;
 /// Common interface for mail items that can be displayed in a mail list.
 /// Implemented by both MailItemViewModel and ThreadMailItemViewModel.
 /// </summary>
-public interface IMailListItem : IMailHashContainer
+public interface IMailListItem : IMailHashContainer, INotifyPropertyChanged
 {
     /// <summary>
     /// Gets the latest creation date for sorting purposes.
@@ -22,4 +24,18 @@ public interface IMailListItem : IMailHashContainer
     /// For ThreadMailItemViewModel: the latest email's from name
     /// </summary>
     string FromName { get; }
+
+    /// <summary>
+    /// Gets whether this item is selected.
+    /// For MailItemViewModel: returns IsSelected
+    /// For ThreadMailItemViewModel: returns IsSelected
+    /// </summary>
+    bool IsSelected { get; set; }
+
+    /// <summary>
+    /// Gets all selected mail items within this list item.
+    /// For MailItemViewModel: returns itself if IsSelected is true, otherwise empty
+    /// For ThreadMailItemViewModel: returns all selected emails within the thread
+    /// </summary>
+    IEnumerable<MailItemViewModel> GetSelectedMailItems();
 }

Wino.Mail.ViewModels/Data/MailItemViewModel.cs

@@ -91,4 +91,12 @@ public partial class MailItemViewModel(MailCopy mailCopy) : ObservableObject, IM
     }
 
     public IEnumerable<Guid> GetContainingIds() => [MailCopy.UniqueId];
+
+    public IEnumerable<MailItemViewModel> GetSelectedMailItems()
+    {
+        if (IsSelected)
+        {
+            yield return this;
+        }
+    }
 }

Wino.Mail.ViewModels/Data/ThreadMailItemViewModel.cs

@@ -118,4 +118,18 @@ public partial class ThreadMailItemViewModel : ObservableRecipient, IDisposable,
     public bool HasUniqueId(Guid uniqueId) => _threadEmails.Any(email => email.MailCopy.UniqueId == uniqueId);
 
     public IEnumerable<Guid> GetContainingIds() => ThreadEmails.Select(a => a.MailCopy.UniqueId);
+
+    public IEnumerable<MailItemViewModel> GetSelectedMailItems()
+    {
+        if (IsSelected)
+        {
+            // If the thread itself is selected, return all emails in the thread
+            return ThreadEmails;
+        }
+        else
+        {
+            // Otherwise, return only individually selected emails within the thread
+            return ThreadEmails.Where(e => e.IsSelected);
+        }
+    }
 }

Wino.Mail.ViewModels/Helpers/ThrottledEventHandler.cs

@@ -1,93 +0,0 @@
-using System;
-using System.Threading;
-using System.Threading.Tasks;
-
-namespace Wino.Mail.ViewModels.Helpers;
-
-/// <summary>
-/// A throttled event handler that delays execution of a callback until a specified time has passed
-/// without the event being triggered again. This is useful for scenarios where events fire rapidly
-/// but you only want to handle the "final" event after a quiet period.
-/// </summary>
-public class ThrottledEventHandler : IDisposable
-{
-    private readonly int _delayMilliseconds;
-    private readonly Func<Task> _asyncCallback;
-    private readonly Action _syncCallback;
-    private Timer _timer;
-    private volatile bool _disposed;
-
-    /// <summary>
-    /// Creates a new throttled event handler with a synchronous callback.
-    /// </summary>
-    /// <param name="delayMilliseconds">The delay in milliseconds to wait before executing the callback</param>
-    /// <param name="callback">The action to execute after the delay period</param>
-    public ThrottledEventHandler(int delayMilliseconds, Action callback)
-    {
-        _delayMilliseconds = delayMilliseconds;
-        _syncCallback = callback ?? throw new ArgumentNullException(nameof(callback));
-    }
-
-    /// <summary>
-    /// Creates a new throttled event handler with an asynchronous callback.
-    /// </summary>
-    /// <param name="delayMilliseconds">The delay in milliseconds to wait before executing the callback</param>
-    /// <param name="callback">The async function to execute after the delay period</param>
-    public ThrottledEventHandler(int delayMilliseconds, Func<Task> callback)
-    {
-        _delayMilliseconds = delayMilliseconds;
-        _asyncCallback = callback ?? throw new ArgumentNullException(nameof(callback));
-    }
-
-    /// <summary>
-    /// Triggers the throttled execution. If called again before the delay period expires,
-    /// the timer is reset and the callback execution is delayed further.
-    /// </summary>
-    public void Trigger()
-    {
-        if (_disposed) return;
-
-        // Dispose existing timer if it exists
-        _timer?.Dispose();
-
-        // Create new timer that will execute the callback after the delay
-        _timer = new Timer(ExecuteCallback, null, _delayMilliseconds, Timeout.Infinite);
-    }
-
-    private async void ExecuteCallback(object state)
-    {
-        if (_disposed) return;
-
-        try
-        {
-            if (_asyncCallback != null)
-            {
-                await _asyncCallback();
-            }
-            else
-            {
-                _syncCallback?.Invoke();
-            }
-        }
-        catch (Exception ex)
-        {
-            // Log error if logging is available, but don't crash
-            System.Diagnostics.Debug.WriteLine($"ThrottledEventHandler callback error: {ex}");
-        }
-        finally
-        {
-            // Dispose the timer since it's one-shot
-            _timer?.Dispose();
-            _timer = null;
-        }
-    }
-
-    public void Dispose()
-    {
-        if (_disposed) return;
-
-        _disposed = true;
-        _timer?.Dispose();
-        _timer = null;
-    }
-}

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -25,7 +25,6 @@ using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Services;
 using Wino.Mail.ViewModels.Collections;
 using Wino.Mail.ViewModels.Data;
-using Wino.Mail.ViewModels.Helpers;
 using Wino.Mail.ViewModels.Messages;
 using Wino.Messaging.Client.Mails;
 using Wino.Messaging.Server;
@@ -55,11 +54,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
     private readonly HashSet<Guid> gmailUnreadFolderMarkedAsReadUniqueIds = [];
 
-    private ThrottledEventHandler _selectionChangedThrottler;
-
-    public event EventHandler ThrottledSelectionChanged;
-    public GroupedEmailCollection MailCollection { get; set; } = new GroupedEmailCollection();
-    //public ObservableCollection<MailItemViewModel> SelectedItems { get; set; } = [];
+    public WinoMailCollection MailCollection { get; set; } = new WinoMailCollection();
     public ObservableCollection<FolderPivotViewModel> PivotFolders { get; set; } = [];
     public ObservableCollection<MailOperationMenuItem> ActionItems { get; set; } = [];
 
@@ -121,7 +116,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     private string barMessage;
 
     [ObservableProperty]
-    private double mailListLength = 420;
+    public partial double MailListLength { get; set; } = 420;
 
     [ObservableProperty]
     private double maxMailListLength = 1200;
@@ -158,11 +153,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
                                  INewThemeService themeService,
                                  IWinoLogger winoLogger)
     {
-        PreferencesService = preferencesService;
-        ThemeService = themeService;
         _winoLogger = winoLogger;
-        StatePersistenceService = statePersistenceService;
-        NavigationService = navigationService;
         _accountService = accountService;
         _mailDialogService = mailDialogService;
         _mailService = mailService;
@@ -171,63 +162,77 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         _winoRequestDelegator = winoRequestDelegator;
         _keyPressService = keyPressService;
 
+        PreferencesService = preferencesService;
+        ThemeService = themeService;
+        StatePersistenceService = statePersistenceService;
+        NavigationService = navigationService;
+
         SelectedFilterOption = FilterOptions[0];
         SelectedSortingOption = SortingOptions[0];
 
-        mailListLength = statePersistenceService.MailListPaneLength;
+        MailListLength = statePersistenceService.MailListPaneLength;
 
-        _selectionChangedThrottler = new ThrottledEventHandler(100, () =>
-        {
-            _ = ExecuteUIThread(() =>
-            {
-                if (MailCollection.SelectedVisibleCount == 1)
-                {
-                    ActiveMailItemChanged(MailCollection.SelectedVisibleItems.ElementAt(0));
-                }
-                else
-                {
-                    // At this point, either we don't have any item selected 
-                    // or we have multiple item selected. In either case
-                    // there should be no active item.
+        //_selectionChangedThrottler = new ThrottledEventHandler(100, () =>
+        //{
+        //    _ = ExecuteUIThread(() =>
+        //    {
+        //        if (MailCollection.SelectedVisibleCount == 1)
+        //        {
+        //            ActiveMailItemChanged(MailCollection.SelectedVisibleItems.ElementAt(0));
+        //        }
+        //        else
+        //        {
+        //            // At this point, either we don't have any item selected 
+        //            // or we have multiple item selected. In either case
+        //            // there should be no active item.
 
-                    ActiveMailItemChanged(null);
-                }
+        //            ActiveMailItemChanged(null);
+        //        }
 
-                NotifyItemSelected();
-                SetupTopBarActions();
-            });
+        //        NotifyItemSelected();
+        //        SetupTopBarActions();
+        //    });
 
-            ThrottledSelectionChanged?.Invoke(this, EventArgs.Empty);
-        });
+        //    ThrottledSelectionChanged?.Invoke(this, EventArgs.Empty);
+        //});
     }
 
     public override void OnNavigatedTo(NavigationMode mode, object parameters)
     {
         base.OnNavigatedTo(mode, parameters);
 
-        MailCollection.SelectionChanged += SelectedItemsChanged;
+        MailCollection.ItemSelectionChanged += MailItemSelectionChanged;
     }
 
     public override void OnNavigatedFrom(NavigationMode mode, object parameters)
     {
         base.OnNavigatedFrom(mode, parameters);
 
-        MailCollection.SelectionChanged -= SelectedItemsChanged;
-        MailCollection.Dispose();
-
-        _selectionChangedThrottler?.Dispose();
-        _selectionChangedThrottler = null;
+        MailCollection.ItemSelectionChanged -= MailItemSelectionChanged;
     }
 
-    private void SelectedItemsChanged(object sender, EventArgs e)
+    private void MailItemSelectionChanged(object sender, EventArgs e)
     {
-        _selectionChangedThrottler?.Trigger();
+        if (MailCollection.HasSingleItemSelected)
+        {
+            var selectedItem = MailCollection.SelectedItems.ElementAtOrDefault(0);
+            ActiveMailItemChanged(selectedItem);
+        }
+        else if (MailCollection.SelectedItemsCount > 1)
+        {
+            ActiveMailItemChanged(null);
+        }
+
+        NotifyItemFoundState();
+        NotifyItemSelected();
+        SetupTopBarActions();
     }
 
     private void SetupTopBarActions()
     {
         ActionItems.Clear();
-        var actions = GetAvailableMailActions(MailCollection.SelectedVisibleItems);
+
+        var actions = GetAvailableMailActions(MailCollection.SelectedItems);
         actions.ForEach(a => ActionItems.Add(a));
     }
 
@@ -270,12 +275,12 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     public bool IsFolderSynchronizationEnabled => ActiveFolder?.IsSynchronizationEnabled ?? false;
     public bool IsArchiveSpecialFolder => ActiveFolder?.SpecialFolderType == SpecialFolderType.Archive;
 
-    public string SelectedMessageText => MailCollection.SelectedVisibleCount > 0 ? string.Format(Translator.MailsSelected, MailCollection.SelectedVisibleCount) : Translator.NoMailSelected;
+    public string SelectedMessageText => MailCollection.SelectedItemsCount > 0 ? string.Format(Translator.MailsSelected, MailCollection.SelectedItemsCount) : Translator.NoMailSelected;
 
     /// <summary>
     /// Indicates current state of the mail list. Doesn't matter it's loading or no.
     /// </summary>
-    public bool IsEmpty => MailCollection.Count == 0;
+    public bool IsEmpty => MailCollection.AllItemsCount == 0;
 
     /// <summary>
     /// Progress ring only should be visible when the folder is initializing and there are no items. We don't need to show it when there are items.
@@ -349,10 +354,6 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     public void NotifyItemSelected()
     {
         OnPropertyChanged(nameof(SelectedMessageText));
-        //OnPropertyChanged(nameof(HasSingleItemSelection));
-        //OnPropertyChanged(nameof(HasSelectedItems));
-        //OnPropertyChanged(nameof(SelectedItemCount));
-        //OnPropertyChanged(nameof(HasMultipleItemSelections));
 
         SelectedFolderPivot?.SelectedItemCount = MailCollection.SelectedItemsCount;
     }
@@ -435,9 +436,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [RelayCommand]
     private async Task ExecuteTopBarAction(MailOperationMenuItem menuItem)
     {
-        if (menuItem == null || MailCollection.SelectedVisibleCount == 0) return;
+        if (menuItem == null || MailCollection.SelectedItemsCount == 0) return;
 
-        await HandleMailOperation(menuItem.Operation, MailCollection.SelectedVisibleItems);
+        await HandleMailOperation(menuItem.Operation, MailCollection.SelectedItems);
     }
 
     /// <summary>
@@ -447,9 +448,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [RelayCommand]
     private async Task ExecuteMailOperation(MailOperation mailOperation)
     {
-        if (!MailCollection.SelectedVisibleItems.Any()) return;
+        if (MailCollection.SelectedItemsCount == 0) return;
 
-        await HandleMailOperation(mailOperation, MailCollection.SelectedVisibleItems);
+        await HandleMailOperation(mailOperation, MailCollection.SelectedItems);
     }
 
     private async Task HandleMailOperation(MailOperation mailOperation, IEnumerable<MailItemViewModel> mailItems)
@@ -564,7 +565,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
         var viewModels = PrepareMailViewModels(items);
 
-        await ExecuteUIThread(() => { MailCollection.AddEmails(viewModels); });
+        await MailCollection.AddRangeAsync(viewModels, false);
         await ExecuteUIThread(() => { IsInitializingFolder = false; });
     }
 
@@ -585,6 +586,14 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         return condition;
     }
 
+    [RelayCommand]
+    public void RemoveFirst()
+    {
+        var fi = MailCollection.GetFirst();
+
+        Messenger.Send(new MailRemovedMessage(fi.MailCopy));
+    }
+
     protected override async void OnMailAdded(MailCopy addedMail)
     {
         base.OnMailAdded(addedMail);
@@ -610,9 +619,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
             await listManipulationSemepahore.WaitAsync();
 
-            await ExecuteUIThread(() =>
+            await ExecuteUIThread(async () =>
             {
-                MailCollection.AddEmail(new MailItemViewModel(addedMail));
+                await MailCollection.AddAsync(addedMail);
                 NotifyItemFoundState();
             });
         }
@@ -629,8 +638,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
         Debug.WriteLine($"Updating {updatedMail.Id}-> {updatedMail.UniqueId}");
 
-        // TODO
-        // await MailCollection.UpdateMailCopy(updatedMail);
+        await MailCollection.UpdateMailCopy(updatedMail);
 
         await ExecuteUIThread(() => { SetupTopBarActions(); });
     }
@@ -656,7 +664,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
         if ((removedFromActiveFolder || removedFromDraftOrSent) && !isDeletedByGmailUnreadFolderAction)
         {
-            bool isDeletedMailSelected = MailCollection.SelectedVisibleItems.Any(a => a.MailCopy.UniqueId == removedMail.UniqueId);
+            bool isDeletedMailSelected = MailCollection.SelectedItems.Any(a => a.MailCopy.UniqueId == removedMail.UniqueId);
 
             // Automatically select the next item in the list if the setting is enabled.
             MailItemViewModel nextItem = null;
@@ -672,7 +680,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
             // Remove the deleted item from the list.
             await ExecuteUIThread(() =>
             {
-                MailCollection.RemoveEmailByMailCopy(removedMail);
+                _ = MailCollection.RemoveAsync(removedMail);
             });
 
             if (nextItem != null)
@@ -684,7 +692,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
                 await ExecuteUIThread(() =>
                 {
-                    MailCollection.ClearSelections();
+                    _ = MailCollection.UnselectAllAsync();
                 });
             }
 
@@ -707,10 +715,10 @@ public partial class MailListPageViewModel : MailBaseViewModel,
             // Otherwise the draft mail item will be duplicated on the next add execution.
             await listManipulationSemepahore.WaitAsync();
 
-            await ExecuteUIThread(() =>
+            await ExecuteUIThread(async () =>
             {
                 // Create the item. Draft folder navigation is already done at this point.
-                MailCollection.AddEmail(new MailItemViewModel(draftMail));
+                await MailCollection.AddAsync(draftMail);
 
                 // New draft is created by user. Select the item.
                 Messenger.Send(new MailItemNavigationRequested(draftMail.UniqueId, ScrollToItem: true));
@@ -745,7 +753,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
         try
         {
-            MailCollection.Clear();
+            _ = MailCollection.ClearAsync();
 
             if (ActiveFolder == null)
                 return;
@@ -847,10 +855,10 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
                 var viewModels = PrepareMailViewModels(items);
 
+                await MailCollection.AddRangeAsync(viewModels, clearIdCache: true);
+
                 await ExecuteUIThread(() =>
                 {
-                    MailCollection.AddEmails(viewModels);
-
                     if (isDoingSearch && !isDoingOnlineSearch)
                     {
                         IsOnlineSearchButtonVisible = true;
@@ -1059,21 +1067,25 @@ public partial class MailListPageViewModel : MailBaseViewModel,
 
             if (handlingFolder == null) return;
 
-            _ = ExecuteUIThread(() =>
+            _ = ExecuteUIThread(async () =>
             {
-                MailCollection.Clear();
+                await MailCollection.ClearAsync();
 
                 _mailDialogService.InfoBarMessage(Translator.AccountCacheReset_Title, Translator.AccountCacheReset_Message, InfoBarMessageType.Warning);
             });
         }
     }
 
+    protected override void OnDispatcherAssigned()
+    {
+        base.OnDispatcherAssigned();
+
+        MailCollection.CoreDispatcher = Dispatcher;
+    }
+
     public void Receive(ThumbnailAdded message)
     {
-        Dispatcher.ExecuteOnUIThread(() =>
-        {
-            MailCollection.UpdateThumbnailsForAddress(message.Email);
-        });
+        _ = MailCollection.UpdateThumbnailsForAddressAsync(message.Email);
     }
 
     protected override void RegisterRecipients()

Wino.Mail.ViewModels/Wino.Mail.ViewModels.csproj

@@ -19,4 +19,7 @@
 		<ProjectReference Include="..\Wino.Messages\Wino.Messaging.csproj" />
 		<ProjectReference Include="..\Wino.Services\Wino.Services.csproj" />
 	</ItemGroup>
+	<ItemGroup>
+	  <Folder Include="Helpers\" />
+	</ItemGroup>
 </Project>

Wino.Mail.WinUI/App.xaml

@@ -12,9 +12,11 @@
                 <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
                 <uwp:CoreGeneric />
                 <ResourceDictionary Source="ms-appx:///CommunityToolkit.WinUI.Controls.Segmented/Segmented/Segmented.xaml" />
+                <ResourceDictionary Source="Controls/ListView/WinoListViewStyles.xaml" />
                 <ResourceDictionary Source="Styles/ItemContainerStyles.xaml" />
                 <ResourceDictionary Source="Styles/ImagePreviewControl.xaml" />
                 <ResourceDictionary Source="Styles/WebViewEditorControl.xaml" />
+                <ResourceDictionary Source="Controls/ListView/WinoListViewStyles.xaml" />
 
                 <styles:WinoExpanderStyle />
                 <ResourceDictionary Source="/Wino.Core.WinUI/AppThemes/Default.xaml" />

Wino.Mail.WinUI/Controls/Advanced/WinoItemsView.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Windows.Input;
 using CommunityToolkit.WinUI;
 using Microsoft.UI.Xaml.Controls;
@@ -6,6 +7,7 @@ using Wino.Mail.ViewModels.Data;
 
 namespace Wino.Mail.WinUI.Controls.Advanced;
 
+[Obsolete("ItemsView sucks. Hard to deal with virtualization issues. Use ListView. This control is here to wise up anyone who tries to use it.")]
 public partial class WinoItemsView : ItemsView
 {
     private const string PART_ScrollView = nameof(PART_ScrollView);

Wino.Mail.WinUI/Controls/ListView/WinoListView.cs

@@ -0,0 +1,49 @@
+using Microsoft.UI.Xaml;
+using Wino.Mail.ViewModels.Data;
+
+namespace Wino.Mail.WinUI.Controls.ListView;
+
+public partial class WinoListView : Microsoft.UI.Xaml.Controls.ListView
+{
+    public bool IsAllSelected => Items.Count == SelectedItems.Count;
+
+    protected override DependencyObject GetContainerForItemOverride() => new WinoListViewItem();
+
+    public bool SelectMailItemContainer(MailItemViewModel mailItemViewModel)
+    {
+        WinoListViewItem? itemContainer = null;
+
+        foreach (var item in Items)
+        {
+            if (item is MailItemViewModel mailItem && mailItem.Id == mailItemViewModel.Id)
+            {
+                itemContainer = ContainerFromItem(mailItemViewModel) as WinoListViewItem;
+
+                break;
+            }
+            else if (item is ThreadMailItemViewModel threadMailItemViewModel && threadMailItemViewModel.HasUniqueId(mailItemViewModel.MailCopy.UniqueId))
+            {
+                itemContainer = ContainerFromItem(threadMailItemViewModel) as WinoListViewItem;
+
+                // Try to get the inner WinoListView.
+                if (itemContainer != null)
+                {
+                    itemContainer.IsExpanded = true;
+
+                    var innerListViewControl = itemContainer.GetWinoListViewControl();
+
+                    if (innerListViewControl != null)
+                    {
+                        itemContainer = innerListViewControl.ContainerFromItem(mailItemViewModel) as WinoListViewItem;
+                    }
+                }
+
+                break;
+            }
+        }
+
+        itemContainer?.IsSelected = true;
+
+        return itemContainer != null;
+    }
+}

Wino.Mail.WinUI/Controls/ListView/WinoListViewItem.cs

@@ -0,0 +1,103 @@
+using CommunityToolkit.Mvvm.Messaging;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Media;
+using Wino.Mail.ViewModels.Data;
+using Wino.Messaging.Client.Mails;
+
+namespace Wino.Mail.WinUI.Controls.ListView;
+
+public partial class WinoListViewItem : ListViewItem
+{
+    public bool IsExpanded
+    {
+        get { return (bool)GetValue(IsExpandedProperty); }
+        set { SetValue(IsExpandedProperty, value); }
+    }
+
+    public static readonly DependencyProperty IsExpandedProperty = DependencyProperty.Register(nameof(IsExpanded), typeof(bool), typeof(WinoListViewItem), new PropertyMetadata(false, OnIsExpandedChanged));
+
+    public WinoListViewItem()
+    {
+        DefaultStyleKey = typeof(WinoListViewItem);
+
+        RegisterPropertyChangedCallback(IsSelectedProperty, OnIsSelectedChanged);
+    }
+
+    private static void OnIsExpandedChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        if (d is WinoListViewItem item)
+        {
+            // Handle expansion state change if needed
+        }
+    }
+
+    protected override void OnContentChanged(object oldContent, object newContent)
+    {
+        base.OnContentChanged(oldContent, newContent);
+
+        if (oldContent is IMailListItem oldMailItem)
+        {
+            UnregisterSelectionCallback(oldMailItem);
+        }
+
+        if (newContent is IMailListItem newMailItem)
+        {
+            IsSelected = newMailItem.IsSelected;
+            RegisterSelectionCallback(newMailItem);
+        }
+    }
+
+    private void UnregisterSelectionCallback(IMailListItem mailItem)
+    {
+        mailItem.PropertyChanged -= MailPropChanged;
+    }
+
+    private void RegisterSelectionCallback(IMailListItem mailItem)
+    {
+        mailItem.PropertyChanged += MailPropChanged;
+    }
+
+    // From model
+    private void MailPropChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+    {
+        if (sender is not IMailListItem mailItem) return;
+
+        if (e.PropertyName == nameof(IMailListItem.IsSelected)) ApplySelectionForContainer(mailItem);
+    }
+
+    // From container.
+    private void OnIsSelectedChanged(DependencyObject sender, DependencyProperty dp)
+    {
+        if (Content is IMailListItem mailItem)
+        {
+            ApplySelectionForModel(mailItem);
+        }
+    }
+
+    private void ApplySelectionForModel(IMailListItem mailItem)
+    {
+        if (mailItem.IsSelected != IsSelected)
+        {
+            mailItem.IsSelected = IsSelected;
+            WeakReferenceMessenger.Default.Send(new SelectedItemsChangedMessage());
+        }
+    }
+
+    private void ApplySelectionForContainer(IMailListItem mailItem)
+    {
+        if (IsSelected != mailItem.IsSelected)
+        {
+            IsSelected = mailItem.IsSelected;
+        }
+    }
+
+    public WinoListView? GetWinoListViewControl()
+    {
+        var expander = GetTemplateChild("ExpanderPart") as Expander;
+
+        if (expander?.Content is ContentPresenter presenter) return VisualTreeHelper.GetChild(presenter, 0) as WinoListView;
+
+        return null;
+    }
+}

Wino.Mail.WinUI/Controls/ListView/WinoListViewStyles.xaml

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ResourceDictionary
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Wino.Mail.WinUI.Controls.ListView">
+
+    <ResourceDictionary.MergedDictionaries>
+        <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
+
+        <ResourceDictionary>
+            <!--  Thread Mail ListViewItem Style  -->
+            <Style x:Key="DefaultThreadListViewItemStyle" TargetType="local:WinoListViewItem">
+                <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}" />
+                <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}" />
+                <Setter Property="Background" Value="{ThemeResource ListViewItemBackground}" />
+                <Setter Property="Foreground" Value="{ThemeResource ListViewItemForeground}" />
+                <Setter Property="TabNavigation" Value="Local" />
+                <Setter Property="IsHoldingEnabled" Value="True" />
+                <Setter Property="Padding" Value="16,0,12,0" />
+                <Setter Property="HorizontalContentAlignment" Value="Stretch" />
+                <Setter Property="VerticalContentAlignment" Value="Center" />
+                <Setter Property="MinWidth" Value="{ThemeResource ListViewItemMinWidth}" />
+                <Setter Property="MinHeight" Value="{ThemeResource ListViewItemMinHeight}" />
+                <Setter Property="AllowDrop" Value="False" />
+                <Setter Property="UseSystemFocusVisuals" Value="True" />
+                <Setter Property="FocusVisualMargin" Value="1" />
+                <Setter Property="FocusVisualPrimaryBrush" Value="{ThemeResource ListViewItemFocusVisualPrimaryBrush}" />
+                <Setter Property="FocusVisualPrimaryThickness" Value="2" />
+                <Setter Property="FocusVisualSecondaryBrush" Value="{ThemeResource ListViewItemFocusVisualSecondaryBrush}" />
+                <Setter Property="FocusVisualSecondaryThickness" Value="1" />
+                <Setter Property="Template">
+                    <Setter.Value>
+                        <ControlTemplate TargetType="local:WinoListViewItem">
+                            <Expander Header="Thread" IsExpanded="{TemplateBinding IsExpanded}">
+                                <Expander.Content>
+                                    <!--  Expandable Content  -->
+                                    <ContentPresenter
+                                        x:Name="ThreadContent"
+                                        Margin="{TemplateBinding Padding}"
+                                        HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
+                                        VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
+                                        Content="{TemplateBinding Content}"
+                                        ContentTemplate="{TemplateBinding ContentTemplate}"
+                                        ContentTransitions="{TemplateBinding ContentTransitions}" />
+                                </Expander.Content>
+                            </Expander>
+                        </ControlTemplate>
+                    </Setter.Value>
+                </Setter>
+            </Style>
+
+            <!--  Default Single Mail List View Item Style.  -->
+            <Style
+                x:Key="DefaultMailListViewItemStyle"
+                BasedOn="{StaticResource DefaultListViewItemStyle}"
+                TargetType="local:WinoListViewItem" />
+
+            <local:WinoMailItemContainerStyleSelector
+                x:Name="WinoMailItemContainerStyleSelector"
+                MailItemStyle="{StaticResource DefaultMailListViewItemStyle}"
+                ThreadStyle="{StaticResource DefaultThreadListViewItemStyle}" />
+        </ResourceDictionary>
+    </ResourceDictionary.MergedDictionaries>
+
+
+</ResourceDictionary>

Wino.Mail.WinUI/Controls/ListView/WinoMailItemContainerStyleSelector.cs

@@ -0,0 +1,19 @@
+using System;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Wino.Mail.ViewModels.Data;
+
+namespace Wino.Mail.WinUI.Controls.ListView;
+
+public partial class WinoMailItemContainerStyleSelector : StyleSelector
+{
+    public Style? ThreadStyle { get; set; }
+    public Style? MailItemStyle { get; set; }
+    protected override Style SelectStyleCore(object item, DependencyObject container)
+    {
+        if (item is MailItemViewModel) return MailItemStyle ?? throw new Exception($"Missing style for {nameof(MailItemViewModel)}");
+        if (item is ThreadMailItemViewModel) return ThreadStyle ?? throw new Exception($"Missing style for {nameof(ThreadMailItemViewModel)}");
+
+        return null;
+    }
+}

Wino.Mail.WinUI/Controls/ListView/WinoMailItemTemplateSelector.cs

@@ -0,0 +1,22 @@
+using System;
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Wino.Mail.ViewModels.Data;
+
+namespace Wino.Mail.WinUI.Controls.ListView;
+
+public partial class WinoMailItemTemplateSelector : DataTemplateSelector
+{
+    public DataTemplate? SingleMailItemTemplate { get; set; }
+    public DataTemplate? ThreadMailItemTemplate { get; set; }
+
+    protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
+    {
+        if (item is MailItemViewModel)
+            return SingleMailItemTemplate ?? throw new Exception($"Missing template for single mail items.");
+        else if (item is ThreadMailItemViewModel)
+            return ThreadMailItemTemplate ?? throw new Exception($"Missing template for thread mail items.");
+
+        return base.SelectTemplateCore(item, container);
+    }
+}

Wino.Mail.WinUI/Selectors/MailItemContainerStyleSelector.cs

@@ -1,18 +0,0 @@
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Wino.Mail.ViewModels.Data;
-
-namespace Wino.Selectors;
-
-public partial class MailItemContainerStyleSelector : StyleSelector
-{
-    public Style Thread { get; set; }
-
-    protected override Style SelectStyleCore(object item, DependencyObject container)
-    {
-        if (item is ThreadMailItemViewModel)
-            return Thread;
-        else
-            return base.SelectStyleCore(item, container);
-    }
-}

Wino.Mail.WinUI/Selectors/MailItemDisplaySelector.cs

@@ -1,21 +0,0 @@
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Wino.Mail.ViewModels.Data;
-
-namespace Wino.Selectors;
-
-public partial class MailItemDisplaySelector : DataTemplateSelector
-{
-    public DataTemplate SingleMailItemTemplate { get; set; }
-    public DataTemplate ThreadMailItemTemplate { get; set; }
-
-    protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
-    {
-        if (item is MailItemViewModel)
-            return SingleMailItemTemplate;
-        else if (item is ThreadMailItemViewModel)
-            return ThreadMailItemTemplate;
-
-        return base.SelectTemplateCore(item, container);
-    }
-}

Wino.Mail.WinUI/Views/ComposePage.xaml.cs

@@ -234,8 +234,14 @@ public sealed partial class ComposePage : ComposePageAbstract,
 
         FocusManager.GotFocus += GlobalFocusManagerGotFocus;
 
-        var anim = ConnectedAnimationService.GetForCurrentView().GetAnimation("WebViewConnectedAnimation");
-        anim?.TryStart(GetWebView());
+        var webView = GetWebView();
+
+        if (webView != null)
+        {
+            var anim = ConnectedAnimationService.GetForCurrentView().GetAnimation("WebViewConnectedAnimation");
+
+            anim?.TryStart(webView);
+        }
 
         _disposables.Add(GetSuggestionBoxDisposable(ToBox));
         _disposables.Add(GetSuggestionBoxDisposable(CCBox));

Wino.Mail.WinUI/Views/MailListPage.xaml

@@ -17,6 +17,7 @@
     xmlns:helpers="using:Wino.Helpers"
     xmlns:i="using:Microsoft.Xaml.Interactivity"
     xmlns:interactivity="using:Microsoft.Xaml.Interactivity"
+    xmlns:listview="using:Wino.Mail.WinUI.Controls.ListView"
     xmlns:local="using:Wino.Behaviors"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:menuflyouts="using:Wino.MenuFlyouts"
@@ -49,147 +50,55 @@
 
         <SolidColorBrush x:Key="ButtonBackgroundDisabled">Transparent</SolidColorBrush>
 
-        <!--
-            Virtualization is disabled because it messes up the selected items.
-            When item is unrealized, it's selection state is lost.
-            I don't want to intercept ItemContainer for it.
-        -->
-
-        <StackLayout
-            x:Key="DefaultItemsViewLayout"
-            IsVirtualizationEnabled="False"
-            Orientation="Vertical"
-            Spacing="6" />
-
-        <!--  Templates  -->
-        <DataTemplate x:Key="EmailTemplate" x:DataType="viewModelData:MailItemViewModel">
-            <ItemContainer
-                HorizontalContentAlignment="Stretch"
-                VerticalContentAlignment="Stretch"
-                CanUserInvoke="UserCanInvoke"
-                IsSelected="{x:Bind IsSelected, Mode=TwoWay}">
-
-                <controls:MailItemDisplayInformationControl
-                    Margin="{x:Bind helpers:XamlHelpers.GetMailItemControlMargin(IsDisplayedInThread), Mode=OneWay}"
-                    x:DefaultBindMode="OneWay"
-                    CenterHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.CenterHoverAction, Mode=OneWay}"
-                    ContextRequested="MailItemContextRequested"
-                    DataContext="{x:Bind}"
-                    DisplayMode="{Binding ElementName=root, Path=ViewModel.PreferencesService.MailItemDisplayMode, Mode=OneWay}"
-                    HoverActionExecutedCommand="{Binding ElementName=root, Path=ViewModel.ExecuteHoverActionCommand}"
-                    IsAvatarVisible="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowSenderPicturesEnabled, Mode=OneWay}"
-                    IsHoverActionsEnabled="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsHoverActionsEnabled, Mode=OneWay}"
-                    IsThumbnailUpdated="{x:Bind ThumbnailUpdatedEvent, Mode=OneWay}"
-                    LeftHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.LeftHoverAction, Mode=OneWay}"
-                    MailItem="{x:Bind MailCopy, Mode=OneWay}"
-                    Prefer24HourTimeFormat="{Binding ElementName=root, Path=ViewModel.PreferencesService.Prefer24HourTimeFormat, Mode=OneWay}"
-                    RightHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.RightHoverAction, Mode=OneWay}"
-                    ShowPreviewText="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowPreviewEnabled, Mode=OneWay}" />
-            </ItemContainer>
+        <!--  Single Mail Item Template  -->
+        <DataTemplate x:Key="SingleMailItemTemplate" x:DataType="viewModelData:MailItemViewModel">
+            <controls:MailItemDisplayInformationControl
+                x:DefaultBindMode="OneWay"
+                CenterHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.CenterHoverAction, Mode=OneWay}"
+                ContextRequested="MailItemContextRequested"
+                DisplayMode="{Binding ElementName=root, Path=ViewModel.PreferencesService.MailItemDisplayMode, Mode=OneWay}"
+                HoverActionExecutedCommand="{Binding ElementName=root, Path=ViewModel.ExecuteHoverActionCommand}"
+                IsAvatarVisible="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowSenderPicturesEnabled, Mode=OneWay}"
+                IsHoverActionsEnabled="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsHoverActionsEnabled, Mode=OneWay}"
+                IsThumbnailUpdated="{x:Bind ThumbnailUpdatedEvent, Mode=OneWay}"
+                LeftHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.LeftHoverAction, Mode=OneWay}"
+                MailItem="{x:Bind MailCopy, Mode=OneWay}"
+                Prefer24HourTimeFormat="{Binding ElementName=root, Path=ViewModel.PreferencesService.Prefer24HourTimeFormat, Mode=OneWay}"
+                RightHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.RightHoverAction, Mode=OneWay}"
+                ShowPreviewText="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowPreviewEnabled, Mode=OneWay}" />
         </DataTemplate>
 
-        <DataTemplate x:Key="ThreadExpanderTemplate" x:DataType="viewModelData:ThreadMailItemViewModel">
-            <ItemContainer
-                CanUserSelect="UserCannotSelect"
-                RightTapped="ThreadContainerRightTapped"
-                Tag="{x:Bind}"
-                Tapped="ThreadContainerTapped">
-                <Grid Padding="4,0,0,0" ColumnSpacing="8">
-                    <Grid.ColumnDefinitions>
-                        <ColumnDefinition Width="Auto" />
-                        <ColumnDefinition Width="*" />
-                    </Grid.ColumnDefinitions>
-
-                    <!--  Expansion indicator  -->
-                    <Viewbox Width="12" Height="12">
-                        <FontIcon
-                            x:Name="ExpanderIcon"
-                            FontFamily="{ThemeResource SymbolThemeFontFamily}"
-                            FontSize="12"
-                            Foreground="{ThemeResource TextFillColorSecondaryBrush}"
-                            Glyph="&#xE76C;" />
-                    </Viewbox>
-
-                    <controls:MailItemDisplayInformationControl
-                        Grid.Column="1"
-                        x:DefaultBindMode="OneWay"
-                        CenterHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.CenterHoverAction, Mode=OneWay}"
-                        ContextRequested="MailItemContextRequested"
-                        DataContext="{x:Bind}"
-                        DisplayMode="{Binding ElementName=root, Path=ViewModel.PreferencesService.MailItemDisplayMode, Mode=OneWay}"
-                        HoverActionExecutedCommand="{Binding ElementName=root, Path=ViewModel.ExecuteHoverActionCommand}"
-                        IsAvatarVisible="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowSenderPicturesEnabled, Mode=OneWay}"
-                        IsHoverActionsEnabled="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsHoverActionsEnabled, Mode=OneWay}"
-                        IsThumbnailUpdated="{x:Bind LatestMailViewModel.ThumbnailUpdatedEvent, Mode=OneWay}"
-                        LeftHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.LeftHoverAction, Mode=OneWay}"
-                        MailItem="{x:Bind LatestMailViewModel.MailCopy, Mode=OneWay}"
-                        Prefer24HourTimeFormat="{Binding ElementName=root, Path=ViewModel.PreferencesService.Prefer24HourTimeFormat, Mode=OneWay}"
-                        RightHoverAction="{Binding ElementName=root, Path=ViewModel.PreferencesService.RightHoverAction, Mode=OneWay}"
-                        ShowPreviewText="{Binding ElementName=root, Path=ViewModel.PreferencesService.IsShowPreviewEnabled, Mode=OneWay}" />
-                </Grid>
-            </ItemContainer>
+        <DataTemplate x:Key="ThreadMailItemTemplate" x:DataType="viewModelData:ThreadMailItemViewModel">
+            <TextBlock Text="thread :)" />
         </DataTemplate>
 
-        <DataTemplate x:Key="DateGroupHeaderTemplate" x:DataType="data:DateGroupHeader">
-            <ItemContainer
-                CanUserSelect="UserCannotSelect"
-                IsHitTestVisible="False"
-                IsSelected="False">
-                <Grid Padding="12,8" Background="{ThemeResource CardBackgroundFillColorDefaultBrush}">
-                    <TextBlock
-                        FontSize="14"
-                        FontWeight="SemiBold"
-                        Foreground="{ThemeResource TextFillColorPrimaryBrush}"
-                        Opacity="1"
-                        Style="{ThemeResource CaptionTextBlockStyle}"
-                        Text="{x:Bind DisplayName, Mode=OneWay}" />
-                </Grid>
-            </ItemContainer>
-        </DataTemplate>
+        <listview:WinoMailItemTemplateSelector
+            x:Key="MailItemTemplateSelector"
+            SingleMailItemTemplate="{StaticResource SingleMailItemTemplate}"
+            ThreadMailItemTemplate="{StaticResource ThreadMailItemTemplate}" />
 
-        <DataTemplate x:Key="SenderGroupHeaderTemplate" x:DataType="data:SenderGroupHeader">
-            <ItemContainer
-                CanUserSelect="UserCannotSelect"
-                IsEnabled="False"
-                IsHitTestVisible="False">
-                <Grid Padding="12,8" Background="{ThemeResource CardBackgroundFillColorDefaultBrush}">
-                    <Grid.ColumnDefinitions>
-                        <ColumnDefinition Width="*" />
-                        <ColumnDefinition Width="Auto" />
-                    </Grid.ColumnDefinitions>
-                    <TextBlock
-                        Foreground="{ThemeResource TextFillColorPrimaryBrush}"
-                        Style="{ThemeResource SubtitleTextBlockStyle}"
-                        Text="{x:Bind DisplayName, Mode=OneWay}" />
-                    <StackPanel
-                        Grid.Column="1"
-                        Orientation="Horizontal"
-                        Spacing="8">
-                        <TextBlock
-                            Foreground="{ThemeResource TextFillColorSecondaryBrush}"
-                            Style="{ThemeResource CaptionTextBlockStyle}"
-                            Text="{x:Bind ItemCount, Mode=OneWay}" />
-                    </StackPanel>
-                </Grid>
-            </ItemContainer>
-        </DataTemplate>
+        <CollectionViewSource
+            x:Name="MailCollectionViewSource"
+            IsSourceGrouped="True"
+            Source="{x:Bind ViewModel.MailCollection.MailItems, Mode=OneWay}" />
 
-        <selectors1:MailItemContainerSelector
-            x:Name="MailItemContainerSelector"
-            DateGroupHeaderTemplate="{StaticResource DateGroupHeaderTemplate}"
-            EmailTemplate="{StaticResource EmailTemplate}"
-            SenderGroupHeaderTemplate="{StaticResource SenderGroupHeaderTemplate}"
-            ThreadExpanderTemplate="{StaticResource ThreadExpanderTemplate}" />
+        <DataTemplate x:Key="MailGroupHeaderDefaultTemplate" x:DataType="collections:IReadOnlyObservableGroup">
+            <Grid
+                Margin="4,2"
+                AllowFocusOnInteraction="False"
+                Background="{ThemeResource MailListHeaderBackgroundColor}"
+                CornerRadius="6">
+                <TextBlock
+                    Padding="12"
+                    VerticalAlignment="Center"
+                    AllowFocusOnInteraction="False"
+                    FontSize="13"
+                    FontWeight="SemiBold"
+                    Text="{x:Bind helpers:XamlHelpers.GetMailGroupDateString(Key)}" />
+            </Grid>
+        </DataTemplate>
     </Page.Resources>
 
-    <Page.KeyboardAccelerators>
-        <KeyboardAccelerator
-            Key="A"
-            Invoked="SelectAllInvoked"
-            Modifiers="Control" />
-
-        <KeyboardAccelerator Key="Delete" Invoked="DeleteAllInvoked" />
-    </Page.KeyboardAccelerators>
     <wino:BasePage.ShellContent>
         <Grid HorizontalAlignment="Stretch">
             <!--  Hidden focus receiver...  -->
@@ -257,7 +166,7 @@
                     <CommandBar
                         HorizontalAlignment="Left"
                         DefaultLabelPosition="Collapsed"
-                        IsEnabled="{x:Bind helpers:XamlHelpers.CountToBooleanConverter(ViewModel.MailCollection.SelectedVisibleItems.Count), Mode=OneWay}"
+                        IsEnabled="{x:Bind helpers:XamlHelpers.CountToBooleanConverter(ViewModel.MailCollection.SelectedItemsCount), Mode=OneWay}"
                         OverflowButtonVisibility="Auto">
                         <interactivity:Interaction.Behaviors>
                             <local:BindableCommandBarBehavior ItemClickedCommand="{x:Bind ViewModel.ExecuteTopBarActionCommand}" PrimaryCommands="{x:Bind ViewModel.ActionItems, Mode=OneWay}" />
@@ -286,7 +195,6 @@
                         VerticalAlignment="Center"
                         Canvas.ZIndex="100"
                         Checked="SelectAllCheckboxChecked"
-                        IsChecked="{x:Bind ViewModel.MailCollection.IsAllItemsSelected, Mode=OneWay}"
                         Unchecked="SelectAllCheckboxUnchecked" />
 
 
@@ -329,6 +237,7 @@
                         Grid.Row="1"
                         Grid.Column="2"
                         Orientation="Horizontal">
+                        <Button Command="{x:Bind ViewModel.RemoveFirstCommand}" Content="T" />
                         <Button
                             Width="36"
                             Height="36"
@@ -436,7 +345,37 @@
                         <RowDefinition Height="Auto" />
                     </Grid.RowDefinitions>
 
-                    <advanced:WinoItemsView
+                    <listview:WinoListView
+                        x:Name="MailListView"
+                        HorizontalAlignment="Stretch"
+                        HorizontalContentAlignment="Stretch"
+                        toolkitExt:ListViewExtensions.ItemContainerStretchDirection="Horizontal"
+                        toolkitExt:ScrollViewerExtensions.VerticalScrollBarMargin="0"
+                        ItemContainerStyleSelector="{StaticResource WinoMailItemContainerStyleSelector}"
+                        ItemTemplateSelector="{StaticResource MailItemTemplateSelector}"
+                        ItemsSource="{x:Bind MailCollectionViewSource.View, Mode=OneWay}"
+                        ProcessKeyboardAccelerators="WinoListViewProcessKeyboardAccelerators"
+                        SelectionMode="Extended">
+                        <listview:WinoListView.ItemContainerTransitions>
+                            <TransitionCollection>
+                                <AddDeleteThemeTransition />
+                            </TransitionCollection>
+                        </listview:WinoListView.ItemContainerTransitions>
+                        <listview:WinoListView.ItemsPanel>
+                            <ItemsPanelTemplate>
+                                <ItemsStackPanel Margin="8,0,12,0" AreStickyGroupHeadersEnabled="True" />
+                            </ItemsPanelTemplate>
+                        </listview:WinoListView.ItemsPanel>
+                        <listview:WinoListView.Resources>
+                            <ResourceDictionary>
+                                <Style BasedOn="{StaticResource MailListHeaderStyle}" TargetType="ListViewHeaderItem" />
+                            </ResourceDictionary>
+                        </listview:WinoListView.Resources>
+                        <listview:WinoListView.GroupStyle>
+                            <GroupStyle HeaderTemplate="{StaticResource MailGroupHeaderDefaultTemplate}" HidesIfEmpty="True" />
+                        </listview:WinoListView.GroupStyle>
+                    </listview:WinoListView>
+                    <!--<advanced:WinoItemsView
                         x:Name="MailListView"
                         Margin="4"
                         ItemTemplate="{StaticResource MailItemContainerSelector}"
@@ -444,7 +383,7 @@
                         Layout="{StaticResource DefaultItemsViewLayout}"
                         LoadMoreCommand="{x:Bind ViewModel.LoadMoreItemsCommand}"
                         ProcessKeyboardAccelerators="MailListView_ProcessKeyboardAccelerators"
-                        SelectionMode="Extended" />
+                        SelectionMode="Extended" />-->
 
                     <!--  Try online search panel.  -->
                     <Grid Grid.Row="1" Visibility="{x:Bind ViewModel.IsOnlineSearchButtonVisible, Mode=OneWay}">

Wino.Mail.WinUI/Views/MailListPage.xaml.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.Messaging;
+using CommunityToolkit.WinUI;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
@@ -14,7 +15,6 @@ using Microsoft.UI.Xaml.Navigation;
 using MoreLinq;
 using Windows.Foundation;
 using Windows.System;
-using Wino.Controls;
 using Wino.Core.Domain;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
@@ -24,7 +24,6 @@ using Wino.Core.Domain.Models.Navigation;
 using Wino.Helpers;
 using Wino.Mail.ViewModels.Data;
 using Wino.Mail.ViewModels.Messages;
-using Wino.Mail.WinUI;
 using Wino.MenuFlyouts.Context;
 using Wino.Messaging.Client.Mails;
 using Wino.Views.Abstract;
@@ -39,8 +38,8 @@ public sealed partial class MailListPage : MailListPageAbstract,
 {
     private const double RENDERING_COLUMN_MIN_WIDTH = 375;
 
-    private IStatePersistanceService StatePersistenceService { get; } = App.Current.Services.GetService<IStatePersistanceService>();
-    private IKeyPressService KeyPressService { get; } = App.Current.Services.GetService<IKeyPressService>();
+    private IStatePersistanceService StatePersistenceService { get; } = Core.WinUI.WinoApplication.Current.Services.GetService<IStatePersistanceService>() ?? throw new Exception($"Can't resolve {nameof(KeyPressService)}");
+    private IKeyPressService KeyPressService { get; } = Core.WinUI.WinoApplication.Current.Services.GetService<IKeyPressService>() ?? throw new Exception($"Can't resolve {nameof(KeyPressService)}");
 
     public MailListPage()
     {
@@ -53,27 +52,26 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
         Bindings.Update();
 
+        ViewModel.MailCollection.ItemSelectionChanged += WinoMailCollectionSelectionChanged;
+
+        UpdateSelectAllButtonStatus();
+        UpdateAdaptiveness();
+
         // Delegate to ViewModel.
         if (e.Parameter is NavigateMailFolderEventArgs folderNavigationArgs)
         {
             WeakReferenceMessenger.Default.Send(new ActiveMailFolderChangedEvent(folderNavigationArgs.BaseFolderMenuItem, folderNavigationArgs.FolderInitLoadAwaitTask));
         }
-
-        ViewModel.ThrottledSelectionChanged += ListSelectionChanged;
-    }
-
-    private void ListSelectionChanged(object? sender, EventArgs e)
-    {
-        UpdateSelectAllButtonStatus();
     }
 
     protected override void OnNavigatedFrom(NavigationEventArgs e)
     {
         base.OnNavigatedFrom(e);
 
-        ViewModel.ThrottledSelectionChanged -= ListSelectionChanged;
         this.Bindings.StopTracking();
 
+        ViewModel.MailCollection.ItemSelectionChanged -= WinoMailCollectionSelectionChanged;
+
         RenderingFrame.Navigate(typeof(IdlePage));
 
         GC.Collect();
@@ -84,20 +82,19 @@ public sealed partial class MailListPage : MailListPageAbstract,
         // Check all checkbox if all is selected.
         // Unhook events to prevent selection overriding.
 
-        //DispatcherQueue.TryEnqueue(Microsoft.UI.Dispatching.DispatcherQueuePriority.Low, () =>
-        //{
-        //    SelectAllCheckbox.Checked -= SelectAllCheckboxChecked;
-        //    SelectAllCheckbox.Unchecked -= SelectAllCheckboxUnchecked;
+        DispatcherQueue.TryEnqueue(Microsoft.UI.Dispatching.DispatcherQueuePriority.Low, () =>
+        {
+            SelectAllCheckbox.Checked -= SelectAllCheckboxChecked;
+            SelectAllCheckbox.Unchecked -= SelectAllCheckboxUnchecked;
 
-        //    bool isAllSelected = ViewModel.MailCollection.AllItems.All(a => a.IsSelected);
-        //    SelectAllCheckbox.IsChecked = ViewModel.MailCollection.AllItems.Count() > 0 && isAllSelected;
+            SelectAllCheckbox.IsChecked = ViewModel.MailCollection.IsAllItemsSelected;
 
-        //    SelectAllCheckbox.Checked += SelectAllCheckboxChecked;
-        //    SelectAllCheckbox.Unchecked += SelectAllCheckboxUnchecked;
-        //});
+            SelectAllCheckbox.Checked += SelectAllCheckboxChecked;
+            SelectAllCheckbox.Unchecked += SelectAllCheckboxUnchecked;
+        });
     }
 
-    private void SelectionModeToggleChecked(object sender, RoutedEventArgs e) => ChangeSelectionMode(ItemsViewSelectionMode.Multiple);
+    private void SelectionModeToggleChecked(object sender, RoutedEventArgs e) => ChangeSelectionMode(ListViewSelectionMode.Multiple);
 
     private void FolderPivotChanged(object sender, SelectionChangedEventArgs e)
     {
@@ -124,29 +121,29 @@ public sealed partial class MailListPage : MailListPageAbstract,
         ViewModel.SelectedPivotChangedCommand.Execute(null);
     }
 
-    private void ChangeSelectionMode(ItemsViewSelectionMode mode)
+    private void ChangeSelectionMode(ListViewSelectionMode mode)
     {
         MailListView.SelectionMode = mode;
 
         if (ViewModel?.PivotFolders != null)
         {
-            ViewModel.PivotFolders.ForEach(a => a.IsExtendedMode = mode == ItemsViewSelectionMode.Extended);
+            ViewModel.PivotFolders.ForEach(a => a.IsExtendedMode = mode == ListViewSelectionMode.Extended);
         }
     }
 
     private void SelectionModeToggleUnchecked(object sender, RoutedEventArgs e)
     {
-        ChangeSelectionMode(ItemsViewSelectionMode.Extended);
+        ChangeSelectionMode(ListViewSelectionMode.Extended);
     }
 
-    private void SelectAllCheckboxChecked(object sender, RoutedEventArgs e)
+    private async void SelectAllCheckboxChecked(object sender, RoutedEventArgs e)
     {
-        ViewModel.MailCollection.SelectAll();
+        await ViewModel.MailCollection.SelectAllAsync();
     }
 
-    private void SelectAllCheckboxUnchecked(object sender, RoutedEventArgs e)
+    private async void SelectAllCheckboxUnchecked(object sender, RoutedEventArgs e)
     {
-        ViewModel.MailCollection.ClearSelections();
+        await ViewModel.MailCollection.UnselectAllAsync();
     }
 
     private async void MailItemContextRequested(UIElement sender, ContextRequestedEventArgs args)
@@ -156,24 +153,24 @@ public sealed partial class MailListPage : MailListPageAbstract,
         // Context is requested from a single mail point, but we might have multiple selected items.
         // This menu should be calculated based on all selected items by providers.
 
-        if (sender is MailItemDisplayInformationControl control && args.TryGetPosition(sender, out Point p))
-        {
-            if (control.DataContext is MailItemViewModel clickedMailItemContext)
-            {
-                var targetItems = ViewModel.MailCollection.AllItems.Where(a => a.IsSelected);
-                var availableActions = ViewModel.GetAvailableMailActions(targetItems);
+        //if (sender is MailItemDisplayInformationControl control && args.TryGetPosition(sender, out Point p))
+        //{
+        //    if (control.DataContext is MailItemViewModel clickedMailItemContext)
+        //    {
+        //        var targetItems = ViewModel.MailCollection.AllItems.Where(a => a.IsSelected);
+        //        var availableActions = ViewModel.GetAvailableMailActions(targetItems);
 
-                if (!availableActions?.Any() ?? false) return;
+        //        if (!availableActions?.Any() ?? false) return;
 
-                var clickedOperation = await GetMailOperationFromFlyoutAsync(availableActions, control, p.X, p.Y);
+        //        var clickedOperation = await GetMailOperationFromFlyoutAsync(availableActions, control, p.X, p.Y);
 
-                if (clickedOperation == null) return;
+        //        if (clickedOperation == null) return;
 
-                var prepRequest = new MailOperationPreperationRequest(clickedOperation.Operation, targetItems.Select(a => a.MailCopy));
+        //        var prepRequest = new MailOperationPreperationRequest(clickedOperation.Operation, targetItems.Select(a => a.MailCopy));
 
-                await ViewModel.ExecuteMailOperationAsync(prepRequest);
-            }
-        }
+        //        await ViewModel.ExecuteMailOperationAsync(prepRequest);
+        //    }
+        //}
     }
 
     private async Task<MailOperationMenuItem> GetMailOperationFromFlyoutAsync(IEnumerable<MailOperationMenuItem> availableActions,
@@ -277,7 +274,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
     #region Connected Animation Helpers
 
-    private WebView2 GetRenderingPageWebView()
+    private WebView2? GetRenderingPageWebView()
     {
         if (RenderingFrame.Content is MailRenderingPage renderingPage)
             return renderingPage.GetWebView();
@@ -285,7 +282,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
         return null;
     }
 
-    private WebView2 GetComposerPageWebView()
+    private WebView2? GetComposerPageWebView()
     {
         if (RenderingFrame.Content is ComposePage composePage)
             return composePage.GetWebView();
@@ -301,7 +298,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
         await ViewModel.ExecuteUIThread(async () =>
         {
-            MailListView.ClearSelections(message.SelectedMailViewModel, true);
+            // MailListView.ClearSelections(message.SelectedMailViewModel, true);
 
             int retriedSelectionCount = 0;
         trySelection:
@@ -343,7 +340,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
                 if (scrollIndex >= 0)
                 {
-                    MailListView.StartBringItemIntoView(scrollIndex, new BringIntoViewOptions() { AnimationDesired = true });
+                    await MailListView.SmoothScrollIntoViewWithIndexAsync(scrollIndex);
                 }
             }
         });
@@ -436,7 +433,6 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
     }
 
-
     private async void SearchBar_TextChanged(AutoSuggestBox sender, AutoSuggestBoxTextChangedEventArgs args)
     {
         // User clicked 'x' button to clearout the search text.
@@ -510,13 +506,6 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
     }
 
-    private void SelectAllInvoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
-    {
-
-
-        // MailListView.SelectAllWino();
-    }
-
     private void DeleteAllInvoked(KeyboardAccelerator sender, KeyboardAcceleratorInvokedEventArgs args)
         => ViewModel.ExecuteMailOperationCommand.Execute(MailOperation.SoftDelete);
 
@@ -552,7 +541,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
         visual.StartAnimation("RotationAngleInDegrees", rotationAnimation);
     }
 
-    private void ListSelectionChanged(ItemsView sender, ItemsViewSelectionChangedEventArgs args)
+    private void WinoMailCollectionSelectionChanged(object sender, EventArgs args)
     {
         UpdateSelectAllButtonStatus();
         UpdateAdaptiveness();
@@ -565,7 +554,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
             expander.IsThreadExpanded = !expander.IsThreadExpanded;
 
             // Select all.
-            ViewModel.MailCollection.AllItems.Where(a => expander.ThreadEmails.Contains(a)).ForEach(a => a.IsSelected = true);
+            // ViewModel.MailCollection.AllItems.Where(a => expander.ThreadEmails.Contains(a)).ForEach(a => a.IsSelected = true);
         }
     }
 
@@ -586,7 +575,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
     }
 
-    private void MailListView_ProcessKeyboardAccelerators(UIElement sender, ProcessKeyboardAcceleratorEventArgs args)
+    private async void WinoListViewProcessKeyboardAccelerators(UIElement sender, ProcessKeyboardAcceleratorEventArgs args)
     {
         if (args.Key == VirtualKey.Delete)
         {
@@ -594,22 +583,9 @@ public sealed partial class MailListPage : MailListPageAbstract,
         }
         else
         {
-            // ItemsView have weird logic for selection inversion. We need to handle it manually.
             args.Handled = true;
 
-            // TODO: If not all items are selected, select all. Otherwise clear selection.
-            // Handle selections in the GroupedEmailCollection.
-
-            ViewModel.MailCollection.SelectAll();
-
-            //if (!ViewModel.MailCollection.IsAllItemsSelected)
-            //{
-
-            //}
-            //else
-            //{
-            //    ViewModel.MailCollection.ClearSelections();
-            //}
+            await ViewModel.MailCollection.ToggleSelectAllAsync();
         }
     }
 }

Wino.Mail.WinUI/Wino.Mail.WinUI.csproj

@@ -66,6 +66,7 @@
     <Content Remove="Assets\Wide310x150Logo.scale-400.png" />
   </ItemGroup>
   <ItemGroup>
+    <None Remove="Controls\ListView\WinoListViewStyles.xaml" />
     <None Remove="ShellWindow.xaml" />
   </ItemGroup>
 
@@ -123,6 +124,11 @@
 	<ProjectReference Include="..\Wino.Mail.ViewModels\Wino.Mail.ViewModels.csproj" />
 	<ProjectReference Include="..\Wino.Services\Wino.Services.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <Page Update="Controls\ListView\WinoListViewStyles.xaml">
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
+  </ItemGroup>
   <ItemGroup>
     <Page Update="ShellWindow.xaml">
       <Generator>MSBuild:Compile</Generator>

Wino.Messages/Client/Mails/SelectedItemsChangedMessage.cs

@@ -0,0 +1,7 @@
+namespace Wino.Messaging.Client.Mails;
+
+/// <summary>
+/// Selection of items are handled in the view model collection.
+/// This message notifies interested parties that the selection has changed.
+/// </summary>
+public record SelectedItemsChangedMessage;