feat(docking): improve tab management and error handling

Refactored DockGroup to only remove obsolete TabViewItems and restore tab selection more reliably. Updated DockGroup.xaml to enable tab reordering and add-tab button. Switched to CommunityToolkit.WinUI.Controls for GridSplitter and added a style for it. Made DockPanel, DockRegionHighlight, and DockingLayout partial classes. In App.xaml.cs, wrapped initialization in a try-catch to exit on error, and ensured process exit on window close. Improved ProjectBrowser scrollbar behavior and layout settings.

src/Editor/Ghost.Editor/App.xaml.cs

@@ -116,6 +116,8 @@ public partial class App : Application
             return;
         }
 
+        try
+        {
             EditorApplication.Initialize(Host.Services, arguments.ProjectPath, arguments.ProjectName);
 
             // NOTE: We must call DispatcherQueue.GetForCurrentThread() on the UI thread before any await.
@@ -136,6 +138,11 @@ public partial class App : Application
 
             splashWindow.Close();
         }
+        catch (Exception ex)
+        {
+            Environment.Exit(ex.HResult);
+        }
+    }
 
     private void OnClosed(object? sender, WindowEventArgs args)
     {
@@ -153,7 +160,7 @@ public partial class App : Application
         }
         finally
         {
-            //Environment.Exit(0);
+            Environment.Exit(0);
         }
     }
 

src/Editor/Ghost.Editor/Themes/Generic.xaml

@@ -1,7 +1,7 @@
 <ResourceDictionary
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-    xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+    xmlns:controls="using:CommunityToolkit.WinUI.Controls"
     xmlns:ghost="using:Ghost.Editor.Controls"
     xmlns:local="using:Ghost.Editor.Core">
 
@@ -42,6 +42,11 @@
         <Setter Property="TabWidthMode" Value="Compact" />
     </Style>
     <Style TargetType="NumberBox" />
+    <Style TargetType="controls:GridSplitter">
+        <Setter Property="MinHeight" Value="2" />
+        <Setter Property="MinWidth" Value="2" />
+        <Setter Property="Background" Value="{ThemeResource AcrylicBackgroundFillColorBaseBrush}" />
+    </Style>
 
     <!--  Named Style  -->
     <Style

src/Editor/Ghost.Editor/View/Controls/Docking/DockGroup.cs

@@ -115,48 +115,39 @@ public partial class DockGroup : DockContainer
 
         var selectedDoc = _tabView.SelectedItem is TabViewItem selectedItem ? selectedItem.Tag as DockDocument : null;
 
-        // Detach all existing tabs
+        // Remove tabs that are no longer in Children
-        foreach (var item in _tabView.TabItems)
+        for (int i = _tabView.TabItems.Count - 1; i >= 0; i--)
         {
-            if (item is TabViewItem tabItem)
+            if (_tabView.TabItems[i] is TabViewItem tabItem && tabItem.Tag is DockDocument doc)
+            {
+                if (!Children.Contains(doc))
                 {
                     tabItem.Content = null;
+                    _tabView.TabItems.RemoveAt(i);
+                }
             }
         }
-        _tabView.TabItems.Clear();
-
-        TabViewItem? newSelectedItem = null;
 
+        // Add new tabs that aren't in TabItems yet
         foreach (var child in Children)
         {
-            if (child is DockDocument doc)
+            if (child is DockDocument doc && !_tabView.TabItems.Any(t => t is TabViewItem item && item.Tag.Equals(doc)))
             {
-                var tabItem = new TabViewItem
+                var tabItem = new TabViewItem { Tag = doc, Content = doc };
-                {
-                    Tag = doc
-                };
-
                 tabItem.SetBinding(TabViewItem.HeaderProperty, new Microsoft.UI.Xaml.Data.Binding
                 {
                     Source = doc,
                     Path = new PropertyPath(nameof(DockDocument.Title)),
-                    Mode = Microsoft.UI.Xaml.Data.BindingMode.OneWay
+                    Mode = BindingMode.OneWay
                 });
-
-                tabItem.Content = doc;
-
                 _tabView.TabItems.Add(tabItem);
-
-                if (doc == selectedDoc)
-                {
-                    newSelectedItem = tabItem;
-                }
             }
         }
 
-        if (newSelectedItem != null)
+        // Restore selection
+        if (selectedDoc != null && _tabView.TabItems.FirstOrDefault(t => t is TabViewItem item && item.Tag.Equals(selectedDoc)) is TabViewItem newSelected)
         {
-            _tabView.SelectedItem = newSelectedItem;
+            _tabView.SelectedItem = newSelected;
         }
         else if (_tabView.TabItems.Count > 0)
         {

src/Editor/Ghost.Editor/View/Controls/Docking/DockGroup.xaml

@@ -7,15 +7,15 @@
         <Setter Property="Template">
             <Setter.Value>
                 <ControlTemplate TargetType="local:DockGroup">
-                    <Grid>
                     <TabView
                         x:Name="PART_TabView"
+                        HorizontalAlignment="Stretch"
                         VerticalAlignment="Stretch"
                         AllowDrop="True"
                         CanDragTabs="True"
-                            CanReorderTabs="False"
+                        CanReorderTabs="True"
-                            IsAddTabButtonVisible="False" />
+                        IsAddTabButtonVisible="True"
-                    </Grid>
+                        TabWidthMode="Compact" />
                 </ControlTemplate>
             </Setter.Value>
         </Setter>

src/Editor/Ghost.Editor/View/Controls/Docking/DockPanel.cs

@@ -1,6 +1,7 @@
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using CommunityToolkit.WinUI.Controls;
+using Windows.Foundation;
 
 namespace Ghost.Editor.View.Controls.Docking;
 
@@ -8,7 +9,7 @@ namespace Ghost.Editor.View.Controls.Docking;
 /// A container that can host multiple dock modules with splitters.
 /// </summary>
 [TemplatePart(Name = PART_GRID, Type = typeof(Grid))]
-public class DockPanel : DockContainer
+public partial class DockPanel : DockContainer
 {
     private const string PART_GRID = "PART_Grid";
     private const double SPLITTER_THICKNESS = 4;
@@ -116,5 +117,7 @@ public class DockPanel : DockContainer
                 }
             }
         }
+
+        UpdateLayout();
     }
 }

src/Editor/Ghost.Editor/View/Controls/Docking/DockRegionHighlight.cs

@@ -5,7 +5,7 @@ namespace Ghost.Editor.View.Controls.Docking;
 /// <summary>
 /// Represents a visual highlight for a docking region.
 /// </summary>
-public class DockRegionHighlight : Control
+public partial class DockRegionHighlight : Control
 {
     public DockRegionHighlight()
     {

src/Editor/Ghost.Editor/View/Controls/Docking/DockingLayout.cs

@@ -8,7 +8,7 @@ namespace Ghost.Editor.View.Controls.Docking;
 /// </summary>
 [TemplatePart(Name = PART_OVERLAY_CANVAS, Type = typeof(Canvas))]
 [TemplatePart(Name = PART_HIGHLIGHT, Type = typeof(DockRegionHighlight))]
-public class DockingLayout : Control
+public partial class DockingLayout : Control
 {
     private const string PART_OVERLAY_CANVAS = "PART_OverlayCanvas";
     private const string PART_HIGHLIGHT = "PART_Highlight";

src/Editor/Ghost.Editor/View/Controls/ProjectBrowser.xaml

@@ -144,8 +144,6 @@
                     DoubleTapped="PART_FilesView_DoubleTapped"
                     IsDoubleTapEnabled="True"
                     ItemsSource="{x:Bind ViewModel.Files, Mode=OneWay}"
-                    ScrollViewer.HorizontalScrollBarVisibility="Disabled"
-                    ScrollViewer.HorizontalScrollMode="Disabled"
                     SelectionChanged="PART_FilesView_SelectionChanged"
                     SelectionMode="Single">
                     <ItemsView.ItemTemplate>
@@ -191,7 +189,7 @@
                     </ItemsView.ItemTemplate>
                     <ItemsView.Layout>
                         <UniformGridLayout
-                            ItemsStretch="Fill"
+                            ItemsStretch="None"
                             MinColumnSpacing="4"
                             MinItemWidth="72"
                             MinRowSpacing="4" />

src/Editor/Ghost.Editor/View/Controls/ProjectBrowser.xaml.cs

@@ -49,6 +49,9 @@ internal sealed partial class ProjectBrowser : UserControl
     private void ProjectBrowser_Loaded(object sender, RoutedEventArgs e)
     {
         _inspectorService.OnSelectionChanged += _inspectorService_OnSelectionChanged;
+
+        // HACK: Scroll a little bit to trigger ScrollView to update it's scrollbar visibility. Otherwise the scrollbar will show a incorrect state when docking layout changes.
+        PART_FilesView.ScrollView.ScrollBy(1, 0);
     }
 
     private void ProjectBrowser_Unloaded(object sender, RoutedEventArgs e)