feature: remember the last active tab index in lfs-image diff view

Signed-off-by: leo <longshuang@msn.cn>

Author: love-linger

src/ViewModels/Preferences.cs

@@ -261,6 +261,12 @@ public bool UseBlockNavigationInDiffView
             set => SetProperty(ref _useBlockNavigationInDiffView, value);
         }
 
+        public int LFSImageDiffActiveIdx
+        {
+            get => _lfsImageDiffActiveIdx;
+            set => SetProperty(ref _lfsImageDiffActiveIdx, value);
+        }
+
         public Models.ChangeViewMode UnstagedChangeViewMode
         {
             get => _unstagedChangeViewMode;
@@ -687,6 +693,7 @@ private bool RemoveInvalidRepositoriesRecursive(List<RepositoryNode> collection)
         private bool _showHiddenSymbolsInDiffView = false;
         private bool _useFullTextDiff = false;
         private bool _useBlockNavigationInDiffView = false;
+        private int _lfsImageDiffActiveIdx = 0;
 
         private Models.ChangeViewMode _unstagedChangeViewMode = Models.ChangeViewMode.List;
         private Models.ChangeViewMode _stagedChangeViewMode = Models.ChangeViewMode.List;

src/Views/DiffView.axaml

@@ -282,7 +282,7 @@
 
           <!-- LFS Image Diff -->
           <DataTemplate DataType="vm:LFSImageDiff">
-            <TabControl Margin="0,8,0,0">
+            <TabControl Margin="0,8,0,0" SelectedIndex="{Binding Source={x:Static vm:Preferences.Instance}, Path=LFSImageDiffActiveIdx, Mode=TwoWay}">
               <TabControl.Styles>
                 <Style Selector="TabControl /template/ ItemsPresenter#PART_ItemsPresenter > WrapPanel">
                   <Setter Property="HorizontalAlignment" Value="Center"/>