fix(docking): address code quality issues and improve docking robustness

src/Editor/Ghost.Editor/Ghost.Editor.csproj

@@ -36,6 +36,7 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="CommunityToolkit.WinUI.Controls.Primitives" Version="8.2.251219" />
+    <PackageReference Include="CommunityToolkit.WinUI.Controls.Sizers" Version="8.2.251219" />
     <PackageReference Include="CommunityToolkit.WinUI.Controls.TabbedCommandBar" Version="8.2.251219" />
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="10.0.2" />
     <PackageReference Include="Microsoft.Windows.CsWinRT" Version="2.2.0" />

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

@@ -9,6 +9,9 @@ namespace Ghost.Editor.View.Controls.Docking;
 public abstract class DockContainer : DockModule
 {
     private readonly ObservableCollection<DockModule> _children = new();
+    /// <summary>
+    /// Gets the collection of child modules.
+    /// </summary>
     public ReadOnlyObservableCollection<DockModule> Children { get; }
 
     protected DockContainer()
@@ -22,15 +25,27 @@ public abstract class DockContainer : DockModule
         OnChildrenUpdated();
     }
 
+    /// <summary>
+    /// Adds a child module to the end of the container.
+    /// </summary>
+    /// <param name="module">The module to add.</param>
     public virtual void AddChild(DockModule module)
     {
         InsertChild(_children.Count, module);
     }
 
+    /// <summary>
+    /// Inserts a child module at the specified index.
+    /// </summary>
+    /// <param name="index">The zero-based index at which the module should be inserted.</param>
+    /// <param name="module">The module to insert.</param>
     public virtual void InsertChild(int index, DockModule module)
     {
         ArgumentNullException.ThrowIfNull(module);
 
+        if (index < 0 || index > _children.Count)
+            throw new ArgumentOutOfRangeException(nameof(index));
+
         if (module == this)
             throw new ArgumentException("Cannot add a container to itself.", nameof(module));
 
@@ -54,6 +69,10 @@ public abstract class DockContainer : DockModule
         _children.Insert(index, module);
     }
 
+    /// <summary>
+    /// Removes a child module from the container.
+    /// </summary>
+    /// <param name="module">The module to remove.</param>
     public virtual void RemoveChild(DockModule module)
     {
         ArgumentNullException.ThrowIfNull(module);
@@ -74,6 +93,9 @@ public abstract class DockContainer : DockModule
         }
     }
 
+    /// <summary>
+    /// Removes all child modules from the container.
+    /// </summary>
     public void Clear()
     {
         foreach (var child in _children)

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

@@ -11,12 +11,18 @@ public partial class DockDocument : DockModule
     public static readonly DependencyProperty ContentProperty = DependencyProperty.Register(
         nameof(Content), typeof(object), typeof(DockDocument), new PropertyMetadata(null));
 
+    /// <summary>
+    /// Gets or sets the title of the document.
+    /// </summary>
     public string? Title
     {
         get => (string?)GetValue(TitleProperty);
         set => SetValue(TitleProperty, value);
     }
 
+    /// <summary>
+    /// Gets or sets the content of the document.
+    /// </summary>
     public object? Content
     {
         get => GetValue(ContentProperty);

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

@@ -157,5 +157,9 @@ public partial class DockGroup : DockContainer
         {
             _tabView.SelectedItem = newSelectedItem;
         }
+        else
+        {
+            _tabView.SelectedItem = _tabView.TabItems.FirstOrDefault();
+        }
     }
 }

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

@@ -7,6 +7,9 @@ namespace Ghost.Editor.View.Controls.Docking;
 /// </summary>
 public abstract class DockModule : Control
 {
+    /// <summary>
+    /// Gets the container that owns this module.
+    /// </summary>
     public DockContainer? Owner { get; internal set; }
     
     private DockingLayout? _root;
@@ -29,6 +32,9 @@ public abstract class DockModule : Control
 
     protected virtual void OnRootChanged() { }
     
+    /// <summary>
+    /// Detaches this module from its current owner.
+    /// </summary>
     public void Detach()
     {
         Owner?.RemoveChild(this);

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

@@ -16,6 +16,9 @@ public class DockPanel : DockContainer
     public static readonly DependencyProperty OrientationProperty = DependencyProperty.Register(
         nameof(Orientation), typeof(Orientation), typeof(DockPanel), new PropertyMetadata(Orientation.Horizontal, OnOrientationChanged));
 
+    /// <summary>
+    /// Gets or sets the orientation of the panel.
+    /// </summary>
     public Orientation Orientation
     {
         get => (Orientation)GetValue(OrientationProperty);
@@ -89,7 +92,7 @@ public class DockPanel : DockContainer
                 if (i < Children.Count - 1)
                 {
                     _grid.ColumnDefinitions.Add(new ColumnDefinition { Width = GridLength.Auto });
-                    var splitter = new CommunityToolkit.WinUI.Controls.GridSplitter { ResizeDirection = CommunityToolkit.WinUI.Controls.GridSplitter.GridResizeDirection.Columns, Width = SPLITTER_THICKNESS };
+                    var splitter = new GridSplitter { ResizeDirection = GridSplitter.GridResizeDirection.Columns, Width = SPLITTER_THICKNESS };
                     Grid.SetColumn(splitter, i * 2 + 1);
                     _grid.Children.Add(splitter);
                 }
@@ -107,7 +110,7 @@ public class DockPanel : DockContainer
                 if (i < Children.Count - 1)
                 {
                     _grid.RowDefinitions.Add(new RowDefinition { Height = GridLength.Auto });
-                    var splitter = new CommunityToolkit.WinUI.Controls.GridSplitter { ResizeDirection = CommunityToolkit.WinUI.Controls.GridSplitter.GridResizeDirection.Rows, Height = SPLITTER_THICKNESS };
+                    var splitter = new GridSplitter { ResizeDirection = GridSplitter.GridResizeDirection.Rows, Height = SPLITTER_THICKNESS };
                     Grid.SetRow(splitter, i * 2 + 1);
                     _grid.Children.Add(splitter);
                 }

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

@@ -147,8 +147,8 @@ public class DockingLayout : Control
             else
             {
                 // Different orientation, need a new sub-panel
-                targetGroup.Detach();
                 var newPanel = new DockPanel { Orientation = orientation };
+                parentPanel.InsertChild(index, newPanel);
 
                 if (target == DockTarget.Left || target == DockTarget.Top)
                 {
@@ -160,8 +160,6 @@ public class DockingLayout : Control
                     newPanel.AddChild(targetGroup);
                     newPanel.AddChild(newGroup);
                 }
-
-                parentPanel.InsertChild(index, newPanel);
             }
         }
     }
@@ -228,10 +226,9 @@ public class DockingLayout : Control
         HideHighlight();
         var target = CalculateDockTarget(targetGroup, position);
 
-        doc.Detach();
-
         if (target == DockTarget.Center)
         {
+            if (doc.Owner == targetGroup) return;
             targetGroup.AddChild(doc);
         }
         else
@@ -256,7 +253,6 @@ public class DockingLayout : Control
 
     internal void CreateFloatingWindow(DockDocument doc)
     {
-        doc.Detach();
         // To be implemented in Task 6
     }
 }