enhance: improve performance

src/Views/Repository.axaml

@@ -231,7 +231,7 @@
             </TextBox.InnerRightContent>
           </TextBox>
 
-          <Grid Grid.Row="2" RowDefinitions="28,Auto,28,Auto,28,Auto,28,Auto,28,Auto" LayoutUpdated="OnDashboardLayoutUpdated">
+          <Grid Grid.Row="2" x:Name="leftSidebarGroups" RowDefinitions="28,Auto,28,Auto,28,Auto,28,Auto,28,Auto">
             <!-- Local Branches -->
             <ToggleButton Grid.Row="0" Classes="group_expander" IsChecked="{Binding IsLocalBranchGroupExpanded, Mode=TwoWay}">
               <TextBlock Classes="group_header_label" Margin="0" Text="{DynamicResource Text.Repository.LocalBranches}"/>
@@ -245,7 +245,8 @@
                       ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                       ScrollViewer.VerticalScrollBarVisibility="Auto"
                       ContextRequested="OnLocalBranchContextMenuRequested"
-                      SelectionChanged="OnLocalBranchTreeSelectionChanged">
+                      SelectionChanged="OnLocalBranchTreeSelectionChanged"
+                      PropertyChanged="OnLeftSidebarTreeViewPropertyChanged">
               <TreeView.Styles>
                 <Style Selector="TreeViewItem" x:DataType="vm:BranchTreeNode">
                   <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
@@ -325,7 +326,8 @@
                       ScrollViewer.HorizontalScrollBarVisibility="Disabled"
                       ScrollViewer.VerticalScrollBarVisibility="Auto"
                       ContextRequested="OnRemoteBranchContextMenuRequested"
-                      SelectionChanged="OnRemoteBranchTreeSelectionChanged">
+                      SelectionChanged="OnRemoteBranchTreeSelectionChanged"
+                      PropertyChanged="OnLeftSidebarTreeViewPropertyChanged">
               <TreeView.Styles>
                 <Style Selector="TreeViewItem" x:DataType="vm:BranchTreeNode">
                   <Setter Property="IsExpanded" Value="{Binding IsExpanded, Mode=TwoWay}"/>
@@ -401,7 +403,8 @@
                       VerticalScrollBarVisibility="Auto"
                       IsVisible="{Binding IsTagGroupExpanded, Mode=OneWay}"
                       SelectionChanged="OnTagDataGridSelectionChanged"
-                      ContextRequested="OnTagContextRequested">
+                      ContextRequested="OnTagContextRequested"
+                      PropertyChanged="OnLeftSidebarDataGridPropertyChanged">
               <DataGrid.Styles>
                 <Style Selector="DataGridRow">
                   <Setter Property="CornerRadius" Value="4" />
@@ -504,6 +507,7 @@
                       VerticalScrollBarVisibility="Auto"
                       ContextRequested="OnSubmoduleContextRequested"
                       DoubleTapped="OnDoubleTappedSubmodule"
+                      PropertyChanged="OnLeftSidebarDataGridPropertyChanged"
                       IsVisible="{Binding IsSubmoduleGroupExpanded, Mode=OneWay}">
               <DataGrid.Styles>
                 <Style Selector="DataGridRow">
@@ -585,6 +589,7 @@
                       VerticalScrollBarVisibility="Auto"
                       ContextRequested="OnWorktreeContextRequested"
                       DoubleTapped="OnDoubleTappedWorktree"
+                      PropertyChanged="OnLeftSidebarDataGridPropertyChanged"
                       IsVisible="{Binding IsWorktreeGroupExpanded, Mode=OneWay}">
               <DataGrid.Styles>
                 <Style Selector="DataGridRow">

src/Views/Repository.axaml.cs

@@ -18,6 +18,16 @@ namespace SourceGit.Views
             InitializeComponent();
         }
 
+        protected override void OnLoaded(RoutedEventArgs e)
+        {
+            base.OnLoaded(e);
+
+            if (DataContext is ViewModels.Repository repo && !repo.IsSearching)
+            {
+                UpdateLeftSidebarLayout();
+            }            
+        }
+
         private void OpenWithExternalTools(object sender, RoutedEventArgs e)
         {
             if (sender is Button button && DataContext is ViewModels.Repository repo)
@@ -244,15 +254,24 @@ namespace SourceGit.Views
             if (sender is Grid grid && DataContext is ViewModels.Repository repo)
             {
                 var node = grid.DataContext as ViewModels.BranchTreeNode;
-                if (node != null && node.IsBranch)
+                if (node == null)
+                    return;
+
+                if (node.IsBranch)
                 {
                     var branch = node.Backend as Models.Branch;
                     if (branch.IsCurrent)
                         return;
 
                     repo.CheckoutBranch(branch);
-                    e.Handled = true;
                 }
+                else
+                {
+                    node.IsExpanded = !node.IsExpanded;
+                    UpdateLeftSidebarLayout();
+                }
+
+                e.Handled = true;
             }
         }
 
@@ -369,17 +388,34 @@ namespace SourceGit.Views
             }
         }
 
-        private void OnDashboardLayoutUpdated(object sender, EventArgs e) 
+        private void OnLeftSidebarTreeViewPropertyChanged(object sender, AvaloniaPropertyChangedEventArgs e)
+        {
+            if (e.Property == TreeView.ItemsSourceProperty || e.Property == TreeView.IsVisibleProperty)
+            {
+                if (sender is TreeView tree && tree.IsVisible)
+                    UpdateLeftSidebarLayout();
+            }
+        }
+
+        private void OnLeftSidebarDataGridPropertyChanged(object sender, AvaloniaPropertyChangedEventArgs e)
+        {
+            if (e.Property == DataGrid.ItemsSourceProperty || e.Property == DataGrid.IsVisibleProperty)
+            {
+                if (sender is DataGrid datagrid && datagrid.IsVisible)
+                    UpdateLeftSidebarLayout();
+            }
+        }
+
+        private void UpdateLeftSidebarLayout()
         {
             var vm = DataContext as ViewModels.Repository;
             if (vm == null || vm.Settings == null)
                 return;
 
-            var grid = sender as Grid;
+            if (!IsLoaded)
-            if (grid == null || !grid.IsAttachedToVisualTree())
                 return;
 
-            var leftHeight = grid.Bounds.Height - 28.0 * 5;
+            var leftHeight = leftSidebarGroups.Bounds.Height - 28.0 * 5;
             if (vm.IsTagGroupExpanded)
             {
                 var desiredHeight = Math.Min(200.0, tagsList.RowHeight * vm.VisibleTags.Count);