Fix: Fixed issue where grouping by tags wouldn't show all items (#11909)

Author: ferrariofilippo

src/Files.App/Helpers/ItemListDisplayHelpers/BulkConcurrentObservableCollection.cs

@@ -168,7 +168,7 @@ private void AddItemsToGroup(IEnumerable<T> items, CancellationToken token = def
 
 				var key = GetGroupKeyForItem(item);
 				if (key is null)
-					return;
+					continue;
 
 				var groups = GroupedCollection?.Where(x => x.Model.Key == key);
 				if (item is IGroupableItem groupable)

src/Files.App/Helpers/ItemListDisplayHelpers/GroupingHelper.cs

@@ -23,7 +23,7 @@ public static Func<ListedItem, string> GetItemGroupKeySelector(GroupOption optio
 				GroupOption.DateModified => x => dateTimeFormatter.ToTimeSpanLabel(x.ItemDateModifiedReal).Text,
 				GroupOption.FileType => x => x.PrimaryItemAttribute == StorageItemTypes.Folder && !x.IsShortcut ? x.ItemType : x.FileExtension?.ToLowerInvariant() ?? " ",
 				GroupOption.SyncStatus => x => x.SyncStatusString,
-				GroupOption.FileTag => x => x.FileTags?.FirstOrDefault(),
+				GroupOption.FileTag => x => x.FileTags?.FirstOrDefault() ?? "Untagged",
 				GroupOption.OriginalFolder => x => (x as RecycleBinItem)?.ItemOriginalFolder,
 				GroupOption.DateDeleted => x => dateTimeFormatter.ToTimeSpanLabel((x as RecycleBinItem)?.ItemDateDeletedReal ?? DateTimeOffset.Now).Text,
 				GroupOption.FolderPath => x => PathNormalization.GetParentDir(x.ItemPath.TrimPath()),
@@ -94,9 +94,9 @@ public static (Action<GroupedCollection<ListedItem>>, Action<GroupedCollection<L
 
 				GroupOption.FileTag => (x =>
 				{
-					ListedItem first = x.First();
+					ListedItem first = x.FirstOrDefault();
 					x.Model.ShowCountTextBelow = true;
-					x.Model.Text = first.FileTagsUI?.FirstOrDefault()?.Name ?? "None".GetLocalizedResource();
+					x.Model.Text = first.FileTagsUI?.FirstOrDefault()?.Name ?? "Untagged".GetLocalizedResource();
 					//x.Model.Icon = first.FileTagsUI?.FirstOrDefault()?.Color;
 				}, null),
 

src/Files.App/Strings/en-US/Resources.resw

@@ -2854,4 +2854,7 @@
   <data name="ShowFileExtensionWarning" xml:space="preserve">
     <value>Show warning when changing file extensions</value>
   </data>
+  <data name="Untagged" xml:space="preserve">
+    <value>Untagged</value>
+  </data>
 </root>