diff --git a/src/Dock.Avalonia/Controls/DockDockControl.axaml b/src/Dock.Avalonia/Controls/DockDockControl.axaml
index ab6e48cdb..d647abd88 100644
--- a/src/Dock.Avalonia/Controls/DockDockControl.axaml
+++ b/src/Dock.Avalonia/Controls/DockDockControl.axaml
@@ -8,7 +8,8 @@
 
   <ControlTheme x:Key="{x:Type DockDockControl}" TargetType="DockDockControl">
 
-    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" />
+    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" x:DataType="core:IDock" />
+    <Setter Property="(ProportionalStackPanelSplitter.IsEmpty)" Value="{Binding IsEmpty}" x:DataType="core:IDock" />
 
     <Setter Property="Template">
       <ControlTemplate>
diff --git a/src/Dock.Avalonia/Controls/DocumentDockControl.axaml b/src/Dock.Avalonia/Controls/DocumentDockControl.axaml
index 1cf7924a2..ac76ef257 100644
--- a/src/Dock.Avalonia/Controls/DocumentDockControl.axaml
+++ b/src/Dock.Avalonia/Controls/DocumentDockControl.axaml
@@ -1,12 +1,14 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                    xmlns:core="using:Dock.Model.Core">
   <Design.PreviewWith>
     <DocumentDockControl Width="300" Height="300" />
   </Design.PreviewWith>
 
   <ControlTheme x:Key="{x:Type DocumentDockControl}" TargetType="DocumentDockControl">
 
-    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" />
+    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" x:DataType="core:IDock" />
+    <Setter Property="(ProportionalStackPanelSplitter.IsEmpty)" Value="{Binding IsEmpty}" x:DataType="core:IDock" />
 
     <Setter Property="Template">
       <ControlTemplate>
diff --git a/src/Dock.Avalonia/Controls/HostWindow.axaml b/src/Dock.Avalonia/Controls/HostWindow.axaml
index 164ca3b2a..c9ca9cc00 100644
--- a/src/Dock.Avalonia/Controls/HostWindow.axaml
+++ b/src/Dock.Avalonia/Controls/HostWindow.axaml
@@ -53,9 +53,10 @@
 
     <Style Selector="^:toolwindow">
 
-      <Setter Property="SystemDecorations" Value="None" />
+      <Setter Property="SystemDecorations" Value="Full" />
       <Setter Property="ExtendClientAreaToDecorationsHint" Value="True" />
-      <Setter Property="ExtendClientAreaChromeHints" Value="PreferSystemChrome" />
+      <Setter Property="ExtendClientAreaChromeHints" Value="NoChrome" />
+      <Setter Property="ExtendClientAreaTitleBarHeightHint" Value="0" />
 
       <Setter Property="Template">
         <ControlTemplate>
diff --git a/src/Dock.Avalonia/Controls/ProportionalDockControl.axaml b/src/Dock.Avalonia/Controls/ProportionalDockControl.axaml
index d9438fe04..20f3e25a4 100644
--- a/src/Dock.Avalonia/Controls/ProportionalDockControl.axaml
+++ b/src/Dock.Avalonia/Controls/ProportionalDockControl.axaml
@@ -8,7 +8,8 @@
 
   <ControlTheme x:Key="{x:Type ProportionalDockControl}" TargetType="ProportionalDockControl">
 
-    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" />
+    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" x:DataType="core:IDock" />
+    <Setter Property="(ProportionalStackPanelSplitter.IsEmpty)" Value="{Binding IsEmpty}" x:DataType="core:IDock" />
 
     <Setter Property="Template">
       <ControlTemplate>
diff --git a/src/Dock.Avalonia/Controls/ProportionalStackPanel.cs b/src/Dock.Avalonia/Controls/ProportionalStackPanel.cs
index eef931f7d..85a1bc139 100644
--- a/src/Dock.Avalonia/Controls/ProportionalStackPanel.cs
+++ b/src/Dock.Avalonia/Controls/ProportionalStackPanel.cs
@@ -33,12 +33,21 @@ private void AssignProportions(global::Avalonia.Controls.Controls children)
         var assignedProportion = 0.0;
         var unassignedProportions = 0;
 
-        foreach (var control in children)
+        for (var i = 0; i < children.Count; i++)
         {
-            if (control is { } && !ProportionalStackPanelSplitter.IsSplitter(control))
+            var control = children[i];
+            var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(control);
+            var isSplitter = ProportionalStackPanelSplitter.IsSplitter(control, out _);
+
+            if (!isSplitter)
             {
                 var proportion = ProportionalStackPanelSplitter.GetControlProportion(control);
 
+                if (isEmpty)
+                {
+                    proportion = 0.0;
+                }
+
                 if (double.IsNaN(proportion))
                 {
                     unassignedProportions++;
@@ -53,9 +62,13 @@ private void AssignProportions(global::Avalonia.Controls.Controls children)
         if (unassignedProportions > 0)
         {
             var toAssign = assignedProportion;
-            foreach (var control in children.Where(c => double.IsNaN(ProportionalStackPanelSplitter.GetControlProportion(c))))
+            foreach (var control in children.Where(c =>
+                     {
+                         var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(c);
+                         return !isEmpty && double.IsNaN(ProportionalStackPanelSplitter.GetControlProportion(c));
+                     }))
             {
-                if (!ProportionalStackPanelSplitter.IsSplitter(control))
+                if (!ProportionalStackPanelSplitter.IsSplitter(control, out _))
                 {
                     var proportion = (1.0 - toAssign) / unassignedProportions;
                     ProportionalStackPanelSplitter.SetControlProportion(control, proportion);
@@ -66,11 +79,15 @@ private void AssignProportions(global::Avalonia.Controls.Controls children)
 
         if (assignedProportion < 1)
         {
-            var numChildren = (double)children.Count(c => !ProportionalStackPanelSplitter.IsSplitter(c));
+            var numChildren = (double)children.Count(c => !ProportionalStackPanelSplitter.IsSplitter(c, out _));
 
             var toAdd = (1.0 - assignedProportion) / numChildren;
 
-            foreach (var child in children.Where(c => !ProportionalStackPanelSplitter.IsSplitter(c)))
+            foreach (var child in children.Where(c =>
+                     {
+                         var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(c);
+                         return !isEmpty && !ProportionalStackPanelSplitter.IsSplitter(c, out _);
+                     }))
             {
                 var proportion = ProportionalStackPanelSplitter.GetControlProportion(child) + toAdd;
                 ProportionalStackPanelSplitter.SetControlProportion(child, proportion);
@@ -78,11 +95,15 @@ private void AssignProportions(global::Avalonia.Controls.Controls children)
         }
         else if (assignedProportion > 1)
         {
-            var numChildren = (double)children.Count(c => !ProportionalStackPanelSplitter.IsSplitter(c));
+            var numChildren = (double)children.Count(c => !ProportionalStackPanelSplitter.IsSplitter(c, out _));
 
             var toRemove = (assignedProportion - 1.0) / numChildren;
 
-            foreach (var child in children.Where(c => !ProportionalStackPanelSplitter.IsSplitter(c)))
+            foreach (var child in children.Where(c =>
+                     {
+                         var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(c);
+                         return !isEmpty && !ProportionalStackPanelSplitter.IsSplitter(c, out _);
+                     }))
             {
                 var proportion = ProportionalStackPanelSplitter.GetControlProportion(child) - toRemove;
                 ProportionalStackPanelSplitter.SetControlProportion(child, proportion);
@@ -92,26 +113,42 @@ private void AssignProportions(global::Avalonia.Controls.Controls children)
 
     private double GetTotalSplitterThickness(global::Avalonia.Controls.Controls children)
     {
-        var result = children
-            .Where(c => ProportionalStackPanelSplitter.IsSplitter(c))
-            .Select(c =>
+        var previousIsEmpty = false;
+        var totalThickness = 0.0;
+
+        for (var i = 0; i < children.Count; i++)
+        {
+            var c = children[i];
+            var isSplitter = ProportionalStackPanelSplitter.IsSplitter(c, out var proportionalStackPanelSplitter);
+
+            if (isSplitter && proportionalStackPanelSplitter is not null)
             {
-                if (c is ContentPresenter contentPresenter)
+                if (previousIsEmpty)
+                {
+                    previousIsEmpty = false;
+                    continue;
+                }
+
+                if (i + 1 < Children.Count)
                 {
-                    if (contentPresenter.Child is null)
+                    var nextControl = Children[i + 1];
+                    var nextIsEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(nextControl);
+                    if (nextIsEmpty)
                     {
-                        contentPresenter.UpdateChild();
+                        continue;
                     }
-
-                    return contentPresenter.Child as ProportionalStackPanelSplitter;
                 }
+                
+                var thickness = proportionalStackPanelSplitter.Thickness;
+                totalThickness += thickness;
+            }
+            else
+            {
+                previousIsEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(c);
+            }
+        }
 
-                return c as ProportionalStackPanelSplitter;
-            })
-            .Where(x => x != null)
-            .Sum(c => c!.Thickness);
-
-        return double.IsNaN(result) ? 0 : result;
+        return double.IsNaN(totalThickness) ? 0 : totalThickness;
     }
 
     /// <inheritdoc/>
@@ -134,14 +171,14 @@ protected override Size MeasureOverride(Size constraint)
 
         AssignProportions(Children);
 
+        var previousIsEmpty = false;
+        
         // Measure each of the Children
-        foreach (var control in Children)
+        for (var i = 0; i < Children.Count; i++)
         {
-            if (control is null)
-            {
-                continue;
-            }
-            
+            var control = Children[i];
+            var isSplitter = ProportionalStackPanelSplitter.IsSplitter(control, out _);
+
             // Get the child's desired size
             var remainingSize = new Size(
                 Math.Max(0.0, constraint.Width - usedWidth - splitterThickness),
@@ -149,35 +186,70 @@ protected override Size MeasureOverride(Size constraint)
 
             var proportion = ProportionalStackPanelSplitter.GetControlProportion(control);
 
-            if (!ProportionalStackPanelSplitter.IsSplitter(control))
+            var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(control);
+            if (isEmpty)
+            {
+                // TODO: Also handle next is empty.
+                previousIsEmpty = true;
+                var size = new Size();
+                control.Measure(size);
+                continue;
+            }
+
+            if (!isSplitter)
             {
                 Debug.Assert(!double.IsNaN(proportion));
 
                 switch (Orientation)
                 {
                     case Orientation.Horizontal:
-                        control.Measure(constraint.WithWidth(Math.Max(0, (constraint.Width - splitterThickness) * proportion)));
+                    {
+                        var width = Math.Max(0, (constraint.Width - splitterThickness) * proportion);
+                        var size = constraint.WithWidth(width);
+                        control.Measure(size);
                         break;
-
+                    }
                     case Orientation.Vertical:
-                        control.Measure(constraint.WithHeight(Math.Max(0, (constraint.Height - splitterThickness) * proportion)));
+                    {
+                        var height = Math.Max(0, (constraint.Height - splitterThickness) * proportion);
+                        var size = constraint.WithHeight(height);
+                        control.Measure(size);
                         break;
+                    }
                 }
             }
             else
             {
+                var nextIsEmpty = false;
+                if (i + 1 < Children.Count)
+                {
+                    var nextControl = Children[i + 1];
+                    nextIsEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(nextControl);
+                }
+
+                if (previousIsEmpty || nextIsEmpty)
+                {
+                    var size = new Size();
+                    control.Measure(size);
+                    previousIsEmpty = true;
+                    continue;
+                }
+
                 control.Measure(remainingSize);
             }
 
+            previousIsEmpty = false;
+
             var desiredSize = control.DesiredSize;
 
             // Decrease the remaining space for the rest of the children
             switch (Orientation)
             {
                 case Orientation.Horizontal:
+                {
                     maximumHeight = Math.Max(maximumHeight, usedHeight + desiredSize.Height);
 
-                    if (ProportionalStackPanelSplitter.IsSplitter(control))
+                    if (isSplitter)
                     {
                         usedWidth += desiredSize.Width;
                     }
@@ -185,11 +257,14 @@ protected override Size MeasureOverride(Size constraint)
                     {
                         usedWidth += Math.Max(0, (constraint.Width - splitterThickness) * proportion);
                     }
+
                     break;
+                }
                 case Orientation.Vertical:
+                {
                     maximumWidth = Math.Max(maximumWidth, usedWidth + desiredSize.Width);
 
-                    if (ProportionalStackPanelSplitter.IsSplitter(control))
+                    if (isSplitter)
                     {
                         usedHeight += desiredSize.Height;
                     }
@@ -197,7 +272,9 @@ protected override Size MeasureOverride(Size constraint)
                     {
                         usedHeight += Math.Max(0, (constraint.Height - splitterThickness) * proportion);
                     }
+
                     break;
+                }
             }
         }
 
@@ -221,13 +298,42 @@ protected override Size ArrangeOverride(Size arrangeSize)
 
         AssignProportions(Children);
 
-        foreach (var control in Children)
+        var previousIsEmpty = false;
+
+        for (var i = 0; i < Children.Count; i++)
         {
-            if (control is null)
+            var control = Children[i];
+
+            var isEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(control);
+            if (isEmpty)
             {
+                // TODO: Also handle next is empty.
+                previousIsEmpty = true;
+                var rect = new Rect();
+                control.Arrange(rect);
+                index++;
                 continue;
             }
 
+            var isSplitter = ProportionalStackPanelSplitter.IsSplitter(control, out _);
+            
+            var nextIsEmpty = false;
+            if (i + 1 < Children.Count)
+            {
+                var nextControl = Children[i + 1];
+                nextIsEmpty = ProportionalStackPanelSplitter.GetControlIsEmpty(nextControl);
+            }
+
+            if (isSplitter && (previousIsEmpty || nextIsEmpty))
+            {
+                var rect = new Rect();
+                control.Arrange(rect);
+                index++;
+                continue;
+            }
+
+            previousIsEmpty = false;
+
             // Determine the remaining space left to arrange the element
             var remainingRect = new Rect(
                 left,
@@ -246,7 +352,8 @@ protected override Size ArrangeOverride(Size arrangeSize)
                 switch (Orientation)
                 {
                     case Orientation.Horizontal:
-                        if (ProportionalStackPanelSplitter.IsSplitter(control))
+                    {
+                        if (isSplitter)
                         {
                             left += desiredSize.Width;
                             remainingRect = remainingRect.WithWidth(desiredSize.Width);
@@ -254,12 +361,16 @@ protected override Size ArrangeOverride(Size arrangeSize)
                         else
                         {
                             Debug.Assert(!double.IsNaN(proportion));
-                            remainingRect = remainingRect.WithWidth(Math.Max(0, (arrangeSize.Width - splitterThickness) * proportion));
-                            left += Math.Max(0, (arrangeSize.Width - splitterThickness) * proportion);
+                            var width = Math.Max(0, (arrangeSize.Width - splitterThickness) * proportion);
+                            remainingRect = remainingRect.WithWidth(width);
+                            left += width;
                         }
+
                         break;
+                    }
                     case Orientation.Vertical:
-                        if (ProportionalStackPanelSplitter.IsSplitter(control))
+                    {
+                        if (isSplitter)
                         {
                             top += desiredSize.Height;
                             remainingRect = remainingRect.WithHeight(desiredSize.Height);
@@ -267,10 +378,13 @@ protected override Size ArrangeOverride(Size arrangeSize)
                         else
                         {
                             Debug.Assert(!double.IsNaN(proportion));
-                            remainingRect = remainingRect.WithHeight(Math.Max(0, (arrangeSize.Height - splitterThickness) * proportion));
-                            top += Math.Max(0, (arrangeSize.Height - splitterThickness) * proportion);
+                            var height = Math.Max(0, (arrangeSize.Height - splitterThickness) * proportion);
+                            remainingRect = remainingRect.WithHeight(height);
+                            top += height;
                         }
+
                         break;
+                    }
                 }
             }
 
diff --git a/src/Dock.Avalonia/Controls/ProportionalStackPanelSplitter.axaml.cs b/src/Dock.Avalonia/Controls/ProportionalStackPanelSplitter.axaml.cs
index 5bfdf1972..a318b46a0 100644
--- a/src/Dock.Avalonia/Controls/ProportionalStackPanelSplitter.axaml.cs
+++ b/src/Dock.Avalonia/Controls/ProportionalStackPanelSplitter.axaml.cs
@@ -42,6 +42,32 @@ public static void SetProportion(AvaloniaObject control, double value)
         control.SetValue(ProportionProperty, value);
     }
 
+    /// <summary>
+    /// Defines the IsEmpty attached property.
+    /// </summary>
+    public static readonly AttachedProperty<bool> IsEmptyProperty =
+        AvaloniaProperty.RegisterAttached<ProportionalStackPanelSplitter, Control, bool>("IsEmpty", false, false, BindingMode.TwoWay);
+
+    /// <summary>
+    /// Gets the value of the IsEmpty attached property on the specified control.
+    /// </summary>
+    /// <param name="control">The control.</param>
+    /// <returns>The IsEmpty attached property.</returns>
+    public static bool GetIsEmpty(AvaloniaObject control)
+    {
+        return control.GetValue(IsEmptyProperty);
+    }
+
+    /// <summary>
+    /// Sets the value of the IsEmpty attached property on the specified control.
+    /// </summary>
+    /// <param name="control">The control.</param>
+    /// <param name="value">The value of the IsEmpty property.</param>
+    public static void SetIsEmpty(AvaloniaObject control, bool value)
+    {
+        control.SetValue(IsEmptyProperty, value);
+    }
+
     /// <summary>
     /// Defines the <see cref="Thickness"/> property.
     /// </summary>
@@ -87,7 +113,7 @@ public double Thickness
     private Point _startPoint;
     private bool _isMoving;
 
-    internal static bool IsSplitter(Control? control)
+    internal static bool IsSplitter(Control? control, out ProportionalStackPanelSplitter? proportionalStackPanelSplitter)
     {
         if (control is ContentPresenter contentPresenter)
         {
@@ -96,10 +122,21 @@ internal static bool IsSplitter(Control? control)
                 contentPresenter.UpdateChild();
             }
 
-            return contentPresenter.Child is ProportionalStackPanelSplitter;
+            if (contentPresenter.Child is ProportionalStackPanelSplitter childSplitter)
+            {
+                proportionalStackPanelSplitter = childSplitter;
+                return true;
+            }
+        }
+
+        if (control is ProportionalStackPanelSplitter splitter)
+        {
+            proportionalStackPanelSplitter = splitter;
+            return true;
         }
 
-        return control is ProportionalStackPanelSplitter;
+        proportionalStackPanelSplitter = null;
+        return false;
     }
 
     internal static void SetControlProportion(Control? control, double proportion)
@@ -150,6 +187,31 @@ internal static double GetControlProportion(Control? control)
         return double.NaN;
     }
 
+    internal static bool GetControlIsEmpty(Control? control)
+    {
+        if (control is ContentPresenter contentPresenter)
+        {
+            if (contentPresenter.Child is null)
+            {
+                contentPresenter.UpdateChild();
+            }
+
+            if (contentPresenter.Child is not null)
+            {
+                return GetIsEmpty(contentPresenter.Child);
+            }
+
+            return false;
+        }
+
+        if (control is not null)
+        {
+            return GetIsEmpty(control);
+        }
+
+        return false;
+    }
+
     /// <inheritdoc/>
     protected override void OnPointerPressed(PointerPressedEventArgs e)
     {
diff --git a/src/Dock.Avalonia/Controls/ToolChromeControl.axaml.cs b/src/Dock.Avalonia/Controls/ToolChromeControl.axaml.cs
index 94d87ac1f..8431d4389 100644
--- a/src/Dock.Avalonia/Controls/ToolChromeControl.axaml.cs
+++ b/src/Dock.Avalonia/Controls/ToolChromeControl.axaml.cs
@@ -81,7 +81,8 @@ protected override void OnApplyTemplate(TemplateAppliedEventArgs e)
         base.OnApplyTemplate(e);
 
         //On linux we dont attach to the HostWindow because of inconsistent drag behaviour
-        if (VisualRoot is HostWindow window && RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+        if (VisualRoot is HostWindow window 
+            && (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) || RuntimeInformation.IsOSPlatform(OSPlatform.OSX)))
         {
             Grip = e.NameScope.Find<Control>("PART_Grip");
             CloseButton = e.NameScope.Find<Button>("PART_CloseButton");
diff --git a/src/Dock.Avalonia/Controls/ToolDockControl.axaml b/src/Dock.Avalonia/Controls/ToolDockControl.axaml
index e530ca526..4ad5ee920 100644
--- a/src/Dock.Avalonia/Controls/ToolDockControl.axaml
+++ b/src/Dock.Avalonia/Controls/ToolDockControl.axaml
@@ -1,24 +1,38 @@
 <ResourceDictionary xmlns="https://github.com/avaloniaui"
-                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+                    xmlns:core="using:Dock.Model.Core">
   <Design.PreviewWith>
     <ToolDockControl Width="300" Height="300" />
   </Design.PreviewWith>
 
   <ControlTheme x:Key="{x:Type ToolDockControl}" TargetType="ToolDockControl">
 
-    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" />
+    <Setter Property="(ProportionalStackPanelSplitter.Proportion)" Value="{Binding Proportion}" x:DataType="core:IDock" />
+    <Setter Property="(ProportionalStackPanelSplitter.IsEmpty)" Value="{Binding IsEmpty}" x:DataType="core:IDock" />
 
     <Setter Property="Template">
       <ControlTemplate>
-        <DockableControl TrackingMode="Visible" 
-                         ProportionalStackPanelSplitter.Proportion="{Binding Proportion}">
+        <DockableControl Name="PART_DockableControl"
+                         TrackingMode="Visible" 
+                         ProportionalStackPanelSplitter.Proportion="{Binding Proportion}"
+                         x:DataType="core:IDock">
           <ToolChromeControl IsActive="{Binding IsActive}"
-                             IsVisible="{Binding !!VisibleDockables.Count}">
+                             IsVisible="{Binding !!VisibleDockables.Count}"
+                             x:DataType="core:IDock">
             <ToolControl />
           </ToolChromeControl>
         </DockableControl>
       </ControlTemplate>
     </Setter>
+    <!--
+    <Style Selector="^[(ProportionalStackPanelSplitter.IsEmpty)=False] /template/ DockableControl#PART_DockableControl">
+      <Setter Property="Background" Value="Blue" />
+    </Style>
+
+    <Style Selector="^[(ProportionalStackPanelSplitter.IsEmpty)=True] /template/ DockableControl#PART_DockableControl">
+      <Setter Property="Background" Value="Red" />
+    </Style>
+    -->
   </ControlTheme>
 
 </ResourceDictionary>
diff --git a/src/Dock.Avalonia/Controls/ToolDockControl.axaml.cs b/src/Dock.Avalonia/Controls/ToolDockControl.axaml.cs
index 3233b450b..50252c2f1 100644
--- a/src/Dock.Avalonia/Controls/ToolDockControl.axaml.cs
+++ b/src/Dock.Avalonia/Controls/ToolDockControl.axaml.cs
@@ -1,4 +1,7 @@
+using Avalonia;
+using Avalonia.Controls.Presenters;
 using Avalonia.Controls.Primitives;
+using Avalonia.VisualTree;
 
 namespace Dock.Avalonia.Controls;
 
@@ -7,4 +10,45 @@ namespace Dock.Avalonia.Controls;
 /// </summary>
 public class ToolDockControl : TemplatedControl
 {
+    private ProportionalStackPanel? GetPanel()
+    {
+        if (Parent is ContentPresenter presenter)
+        {
+            if (presenter.GetVisualParent() is ProportionalStackPanel panel)
+            {
+                return panel;
+            }
+        }
+        else if (this.GetVisualParent() is ProportionalStackPanel psp)
+        {
+            return psp;
+        }
+
+        return null;
+    }
+
+    /// <inheritdoc/>
+    protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+    {
+        base.OnPropertyChanged(change);
+
+        if (change.Property == ProportionalStackPanelSplitter.IsEmptyProperty)
+        {
+            // TODO: Handle invalidation better.
+            if (GetPanel() is { } panel)
+            {
+                panel.InvalidateMeasure();
+                panel.InvalidateArrange();
+                panel.UpdateLayout();
+
+                panel.InvalidateMeasure();
+                panel.InvalidateArrange();
+                panel.UpdateLayout();
+
+                panel.InvalidateMeasure();
+                panel.InvalidateArrange();
+                panel.UpdateLayout();
+            }
+        }
+    }
 }
diff --git a/src/Dock.Avalonia/Controls/ToolTabStrip.axaml b/src/Dock.Avalonia/Controls/ToolTabStrip.axaml
index 7352604fb..71731072f 100644
--- a/src/Dock.Avalonia/Controls/ToolTabStrip.axaml
+++ b/src/Dock.Avalonia/Controls/ToolTabStrip.axaml
@@ -41,7 +41,7 @@
       </ItemsPanelTemplate>
     </Setter>
 
-    <Style Selector="^:singleitem">
+    <Style Selector="^:singleitem /template/ ItemsPresenter#PART_ItemsPresenter">
       <Setter Property="IsVisible" Value="False" />
     </Style>
 
diff --git a/src/Dock.Model.Avalonia/Core/DockBase.cs b/src/Dock.Model.Avalonia/Core/DockBase.cs
index 174d6185c..9ddedc477 100644
--- a/src/Dock.Model.Avalonia/Core/DockBase.cs
+++ b/src/Dock.Model.Avalonia/Core/DockBase.cs
@@ -68,6 +68,12 @@ public abstract class DockBase : DockableBase, IDock
     public static readonly DirectProperty<DockBase, bool> IsActiveProperty =
         AvaloniaProperty.RegisterDirect<DockBase, bool>(nameof(IsActive), o => o.IsActive, (o, v) => o.IsActive = v);
 
+    /// <summary>
+    /// Defines the <see cref="IsEmpty"/> property.
+    /// </summary>
+    public static readonly DirectProperty<DockBase, bool> IsEmptyProperty =
+        AvaloniaProperty.RegisterDirect<DockBase, bool>(nameof(IsEmpty), o => o.IsEmpty, (o, v) => o.IsEmpty = v);
+
     /// <summary>
     /// Defines the <see cref="IsCollapsable"/> property.
     /// </summary>
@@ -94,6 +100,7 @@ public abstract class DockBase : DockableBase, IDock
     private double _proportion = double.NaN;
     private DockMode _dock = DockMode.Center;
     private bool _isActive;
+    private bool _isEmpty;
     private bool _isCollapsable = true;
     private bool _canGoBack;
     private bool _canGoForward;
@@ -188,6 +195,15 @@ public bool IsActive
         set => SetAndRaise(IsActiveProperty, ref _isActive, value);
     }
 
+    /// <inheritdoc/>
+    [DataMember(IsRequired = false, EmitDefaultValue = true)]
+    [JsonPropertyName("IsEmpty")]
+    public bool IsEmpty
+    {
+        get => _isEmpty;
+        set => SetAndRaise(IsEmptyProperty, ref _isEmpty, value);
+    }
+
     /// <inheritdoc/>
     [DataMember(IsRequired = false, EmitDefaultValue = true)]
     [JsonPropertyName("IsCollapsable")]
diff --git a/src/Dock.Model.Avalonia/Json/AvaloniaDockSerializer.cs b/src/Dock.Model.Avalonia/Json/AvaloniaDockSerializer.cs
index 9a8b0c4d8..823badfef 100644
--- a/src/Dock.Model.Avalonia/Json/AvaloniaDockSerializer.cs
+++ b/src/Dock.Model.Avalonia/Json/AvaloniaDockSerializer.cs
@@ -113,6 +113,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
             },
             [typeof(IDockDock)] = new List<string>
@@ -132,6 +133,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IDockDock
                 "LastChildFill",
@@ -153,6 +155,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IDocumentDock
                 "CanCreateDocument",
@@ -174,6 +177,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
             },
             [typeof(IProportionalDock)] = new List<string>
@@ -193,6 +197,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IProportionalDock
                 "Orientation",
@@ -214,6 +219,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
             },
             [typeof(IRootDock)] = new List<string>
@@ -233,6 +239,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IRootDock
                 "IsFocusableRoot",
@@ -261,6 +268,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IToolDock
                 "Alignment",
@@ -295,6 +303,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
             },
             [typeof(Document)] = new List<string>
@@ -334,6 +343,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IDockDock
                 "LastChildFill",
@@ -355,6 +365,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IDocumentDock
                 "CanCreateDocument",
@@ -376,6 +387,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IProportionalDock
                 "Orientation",
@@ -397,6 +409,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
             },
             [typeof(RootDock)] = new List<string>
@@ -416,6 +429,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IRootDock
                 "IsFocusableRoot",
@@ -444,6 +458,7 @@ public AvaloniaDockSerializer()
                 "Proportion",
                 "Dock",
                 "IsActive",
+                "IsEmpty",
                 "IsCollapsable",
                 // IToolDock
                 "Alignment",
diff --git a/src/Dock.Model.Mvvm/Core/DockBase.cs b/src/Dock.Model.Mvvm/Core/DockBase.cs
index aedd5d363..42cdc928d 100644
--- a/src/Dock.Model.Mvvm/Core/DockBase.cs
+++ b/src/Dock.Model.Mvvm/Core/DockBase.cs
@@ -22,6 +22,7 @@ public abstract class DockBase : DockableBase, IDock
     private DockMode _dock = DockMode.Center;
     private bool _isCollapsable = true;
     private bool _isActive;
+    private bool _isEmpty;
 
     /// <summary>
     /// Initializes new instance of the <see cref="DockBase"/> class.
@@ -101,6 +102,14 @@ public bool IsActive
         set => SetProperty(ref _isActive, value);
     }
 
+    /// <inheritdoc/>
+    [DataMember(IsRequired = false, EmitDefaultValue = true)]
+    public bool IsEmpty
+    {
+        get => _isEmpty;
+        set => SetProperty(ref _isEmpty, value);
+    }
+
     /// <inheritdoc/>
     [DataMember(IsRequired = false, EmitDefaultValue = true)]
     public bool IsCollapsable
diff --git a/src/Dock.Model.ReactiveUI/Core/DockBase.cs b/src/Dock.Model.ReactiveUI/Core/DockBase.cs
index 44d42376e..683895752 100644
--- a/src/Dock.Model.ReactiveUI/Core/DockBase.cs
+++ b/src/Dock.Model.ReactiveUI/Core/DockBase.cs
@@ -22,6 +22,7 @@ public abstract class DockBase : DockableBase, IDock
     private DockMode _dock = DockMode.Center;
     private bool _isCollapsable = true;
     private bool _isActive;
+    private bool _isEmpty;
 
     /// <summary>
     /// Initializes new instance of the <see cref="DockBase"/> class.
@@ -101,6 +102,14 @@ public bool IsActive
         set => this.RaiseAndSetIfChanged(ref _isActive, value);
     }
 
+    /// <inheritdoc/>
+    [DataMember(IsRequired = false, EmitDefaultValue = true)]
+    public bool IsEmpty
+    {
+        get => _isEmpty;
+        set => this.RaiseAndSetIfChanged(ref _isEmpty, value);
+    }
+
     /// <inheritdoc/>
     [DataMember(IsRequired = false, EmitDefaultValue = true)]
     public bool IsCollapsable
diff --git a/src/Dock.Model/Core/IDock.cs b/src/Dock.Model/Core/IDock.cs
index 8b5b4f415..bfc6553a5 100644
--- a/src/Dock.Model/Core/IDock.cs
+++ b/src/Dock.Model/Core/IDock.cs
@@ -43,6 +43,11 @@ public interface IDock : IDockable
     /// </summary>
     bool IsActive { get; set; }
 
+    /// <summary>
+    /// Gets if the dockable is empty.
+    /// </summary>
+    bool IsEmpty { get; set; }
+
     /// <summary>
     /// Gets or sets if the Dock collapses when all its children are removed.
     /// </summary>
diff --git a/src/Dock.Model/FactoryBase.Dockable.cs b/src/Dock.Model/FactoryBase.Dockable.cs
index de96a78c0..e002a05d0 100644
--- a/src/Dock.Model/FactoryBase.Dockable.cs
+++ b/src/Dock.Model/FactoryBase.Dockable.cs
@@ -14,6 +14,7 @@ public virtual void AddDockable(IDock dock, IDockable dockable)
         InitDockable(dockable, dock);
         dock.VisibleDockables ??= CreateList<IDockable>();
         dock.VisibleDockables.Add(dockable);
+        dock.IsEmpty = dock.VisibleDockables.Count == 0;
         OnDockableAdded(dockable);
     }
 
@@ -25,6 +26,7 @@ public virtual void InsertDockable(IDock dock, IDockable dockable, int index)
             InitDockable(dockable, dock);
             dock.VisibleDockables ??= CreateList<IDockable>();
             dock.VisibleDockables.Insert(index, dockable);
+            dock.IsEmpty = dock.VisibleDockables.Count == 0;
             OnDockableAdded(dockable);
         }
     }
@@ -44,6 +46,7 @@ public virtual void RemoveDockable(IDockable dockable, bool collapse)
         }
 
         dock.VisibleDockables.Remove(dockable);
+        dock.IsEmpty = dock.VisibleDockables.Count == 0;
         OnDockableRemoved(dockable);
 
         var indexActiveDockable = index > 0 ? index - 1 : 0;
@@ -100,8 +103,10 @@ public virtual void MoveDockable(IDock dock, IDockable sourceDockable, IDockable
         if (sourceIndex >= 0 && targetIndex >= 0 && sourceIndex != targetIndex)
         {
             dock.VisibleDockables.RemoveAt(sourceIndex);
+            dock.IsEmpty = dock.VisibleDockables.Count == 0;
             OnDockableRemoved(sourceDockable);
             dock.VisibleDockables.Insert(targetIndex, sourceDockable);
+            dock.IsEmpty = dock.VisibleDockables.Count == 0;
             OnDockableAdded(sourceDockable);
             OnDockableMoved(sourceDockable);
             dock.ActiveDockable = sourceDockable;
@@ -173,8 +178,10 @@ public virtual void MoveDockable(IDock sourceDock, IDock targetDock, IDockable s
                 if (sourceIndex < targetIndex)
                 {
                     targetDock.VisibleDockables.Insert(targetIndex + 1, sourceDockable);
+                    targetDock.IsEmpty = targetDock.VisibleDockables.Count == 0;
                     OnDockableAdded(sourceDockable);
                     targetDock.VisibleDockables.RemoveAt(sourceIndex);
+                    targetDock.IsEmpty = targetDock.VisibleDockables.Count == 0;
                     OnDockableRemoved(sourceDockable);
                     OnDockableMoved(sourceDockable);
                 }
@@ -184,8 +191,10 @@ public virtual void MoveDockable(IDock sourceDock, IDock targetDock, IDockable s
                     if (targetDock.VisibleDockables.Count + 1 > removeIndex)
                     {
                         targetDock.VisibleDockables.Insert(targetIndex, sourceDockable);
+                        targetDock.IsEmpty = targetDock.VisibleDockables.Count == 0;
                         OnDockableAdded(sourceDockable);
                         targetDock.VisibleDockables.RemoveAt(removeIndex);
+                        targetDock.IsEmpty = targetDock.VisibleDockables.Count == 0;
                         OnDockableRemoved(sourceDockable);
                         OnDockableMoved(sourceDockable);
                     }
@@ -195,6 +204,7 @@ public virtual void MoveDockable(IDock sourceDock, IDock targetDock, IDockable s
             {
                 RemoveDockable(sourceDockable, true);
                 targetDock.VisibleDockables.Insert(targetIndex, sourceDockable);
+                targetDock.IsEmpty = targetDock.VisibleDockables.Count == 0;
                 OnDockableAdded(sourceDockable);
                 OnDockableMoved(sourceDockable);
                 InitDockable(sourceDockable, targetDock);
@@ -220,9 +230,11 @@ public virtual void SwapDockable(IDock dock, IDockable sourceDockable, IDockable
             var originalTargetDockable = dock.VisibleDockables[targetIndex];
 
             dock.VisibleDockables[targetIndex] = originalSourceDockable;
+            dock.IsEmpty = dock.VisibleDockables.Count == 0;
             OnDockableRemoved(originalTargetDockable);
             OnDockableAdded(originalSourceDockable);
             dock.VisibleDockables[sourceIndex] = originalTargetDockable;
+            dock.IsEmpty = dock.VisibleDockables.Count == 0;
             OnDockableAdded(originalTargetDockable);
             OnDockableSwapped(originalSourceDockable);
             OnDockableSwapped(originalTargetDockable);
@@ -352,6 +364,7 @@ public virtual void PinDockable(IDockable dockable)
                     if (toolDock.VisibleDockables is not null)
                     {
                         toolDock.VisibleDockables.Remove(dockable);
+                        toolDock.IsEmpty = toolDock.VisibleDockables.Count == 0;
                         OnDockableRemoved(dockable);
                     }
 
@@ -456,6 +469,7 @@ public virtual void PinDockable(IDockable dockable)
                     }
 
                     toolDock.VisibleDockables.Add(dockable);
+                    toolDock.IsEmpty = toolDock.VisibleDockables.Count == 0;
                     OnDockableAdded(dockable);
                     
                     // TODO: Handle ActiveDockable state.
diff --git a/src/Dock.Model/FactoryBase.Init.cs b/src/Dock.Model/FactoryBase.Init.cs
index 0d956c57b..634ceb812 100644
--- a/src/Dock.Model/FactoryBase.Init.cs
+++ b/src/Dock.Model/FactoryBase.Init.cs
@@ -53,6 +53,8 @@ public virtual void InitDockable(IDockable dockable, IDockable? owner)
                 {
                     InitDockable(child, dockable);
                 }
+
+                dock.IsEmpty = dock.VisibleDockables.Count == 0;
             }
         }
 
diff --git a/src/Dock.Model/FactoryBase.cs b/src/Dock.Model/FactoryBase.cs
index a66051aaf..15fc26aa0 100644
--- a/src/Dock.Model/FactoryBase.cs
+++ b/src/Dock.Model/FactoryBase.cs
@@ -126,6 +126,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
             if (split.VisibleDockables is not null)
             {
                 split.VisibleDockables.Add(dockable);
+                split.IsEmpty = split.VisibleDockables.Count == 0;
                 OnDockableAdded(dockable);
                 split.ActiveDockable = dockable;
             }
@@ -166,6 +167,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
                 if (layout.VisibleDockables is not null)
                 {
                     layout.VisibleDockables.Add(split);
+                    layout.IsEmpty = layout.VisibleDockables.Count == 0;
                     OnDockableAdded(split);
                     layout.ActiveDockable = split;
                 }
@@ -178,6 +180,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
                 if (layout.VisibleDockables is not null)
                 {
                     layout.VisibleDockables.Add(dock);
+                    layout.IsEmpty = layout.VisibleDockables.Count == 0;
                     OnDockableAdded(dock);
                     layout.ActiveDockable = dock;
                 }
@@ -187,6 +190,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
         }
 
         layout.VisibleDockables?.Add(splitter);
+        layout.IsEmpty = layout.VisibleDockables?.Count == 0;
         OnDockableAdded(splitter);
 
         switch (operation)
@@ -197,6 +201,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
                 if (layout.VisibleDockables is not null)
                 {
                     layout.VisibleDockables.Add(dock);
+                    layout.IsEmpty = layout.VisibleDockables.Count == 0;
                     OnDockableAdded(dock);
                     layout.ActiveDockable = dock;
                 }
@@ -209,6 +214,7 @@ public virtual IDock CreateSplitLayout(IDock dock, IDockable dockable, DockOpera
                 if (layout.VisibleDockables is not null)
                 {
                     layout.VisibleDockables.Add(split);
+                    layout.IsEmpty = layout.VisibleDockables.Count == 0;
                     OnDockableAdded(split);
                     layout.ActiveDockable = split;
                 }
@@ -237,8 +243,10 @@ public virtual void SplitToDock(IDock dock, IDockable dockable, DockOperation op
                     {
                         var layout = CreateSplitLayout(dock, dockable, operation);
                         ownerDock.VisibleDockables.RemoveAt(index);
+                        ownerDock.IsEmpty = ownerDock.VisibleDockables.Count == 0;
                         OnDockableRemoved(dockable);
                         ownerDock.VisibleDockables.Insert(index, layout);
+                        layout.IsEmpty = layout.VisibleDockables?.Count == 0;
                         OnDockableAdded(dockable);
                         InitDockable(layout, ownerDock);
                         ownerDock.ActiveDockable = layout;
@@ -269,6 +277,7 @@ public virtual void SplitToDock(IDock dock, IDockable dockable, DockOperation op
                     if (dock.VisibleDockables is not null)
                     {
                         dock.VisibleDockables.Add(dockable);
+                        dock.IsEmpty = dock.VisibleDockables.Count == 0;
                         OnDockableAdded(dockable);
                         dock.ActiveDockable = dockable;
                     }
@@ -301,6 +310,7 @@ public virtual void SplitToDock(IDock dock, IDockable dockable, DockOperation op
                     if (dock.VisibleDockables is not null)
                     {
                         dock.VisibleDockables.Add(dockable);
+                        dock.IsEmpty = dock.VisibleDockables.Count == 0;
                         OnDockableAdded(dockable);
                         dock.ActiveDockable = dockable;
                     }
@@ -350,6 +360,7 @@ public virtual void SplitToDock(IDock dock, IDockable dockable, DockOperation op
         if (root.VisibleDockables is not null && target is not null)
         {
             root.VisibleDockables.Add(target);
+            root.IsEmpty = root.VisibleDockables.Count == 0;
             OnDockableAdded(target);
             root.ActiveDockable = target;
             root.DefaultDockable = target;