Allow DevTools to inspect popup visual trees.

Perspex.Base/Perspex.Base.csproj

@@ -38,6 +38,7 @@
   <ItemGroup>
     <Compile Include="Binding.cs" />
     <Compile Include="Diagnostics\PerspexObjectExtensions.cs" />
+    <Compile Include="PerspexProperty`1.cs" />
     <Compile Include="PriorityBindingEntry.cs" />
     <Compile Include="Collections\IPerspexList.cs" />
     <Compile Include="Collections\PerspexReadOnlyListView.cs" />

Perspex.Controls/Popup.cs

@@ -12,7 +12,7 @@ namespace Perspex.Controls
     using Perspex.Rendering;
     using Perspex.VisualTree;
 
-    public class Popup : Control, ILogical
+    public class Popup : Control, ILogical, IVisualTreeHost
     {
         public static readonly PerspexProperty<Control> ChildProperty =
             PerspexProperty.Register<Popup, Control>("Child");
@@ -80,6 +80,11 @@ namespace Perspex.Controls
             get { return this.logicalChild; }
         }
 
+        IVisual IVisualTreeHost.Root
+        {
+            get { return this.popupRoot; }
+        }
+
         public void Open()
         {
             if (this.popupRoot == null)

Perspex.Diagnostics/ViewModels/TreeNode.cs

@@ -36,7 +36,7 @@ namespace Perspex.Diagnostics.ViewModels
                 });
         }
 
-        public IReactiveDerivedList<TreeNode> Children
+        public IReadOnlyReactiveList<TreeNode> Children
         {
             get;
             protected set;

Perspex.Diagnostics/ViewModels/VisualTreeNode.cs

@@ -7,6 +7,7 @@
 namespace Perspex.Diagnostics.ViewModels
 {
     using Perspex.Controls;
+    using Perspex.VisualTree;
     using ReactiveUI;
 
     internal class VisualTreeNode : TreeNode
@@ -14,7 +15,16 @@ namespace Perspex.Diagnostics.ViewModels
         public VisualTreeNode(IVisual visual)
             : base((Control)visual)
         {
-            this.Children = visual.VisualChildren.CreateDerivedCollection(x => new VisualTreeNode(x));
+            var host = visual as IVisualTreeHost;
+
+            if (host == null || host.Root == null)
+            {
+                this.Children = visual.VisualChildren.CreateDerivedCollection(x => new VisualTreeNode(x));
+            }
+            else
+            {
+                this.Children = new ReactiveList<VisualTreeNode>(new[] { new VisualTreeNode(host.Root) });
+            }
 
             if (this.Control != null)
             {

Perspex.SceneGraph/Perspex.SceneGraph.csproj

@@ -100,6 +100,7 @@
     <Compile Include="Thickness.cs" />
     <Compile Include="Vector.cs" />
     <Compile Include="Visual.cs" />
+    <Compile Include="VisualTree\IVisualTreeHost.cs" />
     <Compile Include="VisualTree\TransformedBounds.cs" />
     <Compile Include="VisualTree\BoundsTracker.cs" />
     <Compile Include="VisualTree\VisualExtensions.cs" />

Perspex.SceneGraph/VisualTree/IVisualTreeHost.cs

@@ -0,0 +1,22 @@
+// -----------------------------------------------------------------------
+// <copyright file="IVisualTreeHost.cs" company="Steven Kirk">
+// Copyright 2015 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.VisualTree
+{
+    /// <summary>
+    /// Interface for controls that host their own separate visual tree, such as popups.
+    /// </summary>
+    public interface IVisualTreeHost
+    {
+        /// <summary>
+        /// Gets the root of the hosted visual tree.
+        /// </summary>
+        /// <value>
+        /// The root of the hosted visual tree.
+        /// </value>
+        IVisual Root { get; }
+    }
+}