From 0f81420ee2615432f4066a06a61bc5f1b13114d0 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Thu, 15 Jun 2017 01:26:39 +0200
Subject: [PATCH] Don't remove root layer when hiding root.

---
 .../Rendering/SceneGraph/SceneBuilder.cs      |  2 +-
 .../SceneGraph/SceneBuilderTests_Layers.cs    | 27 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
index e54648fe8d..720993b31a 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneBuilder.cs
@@ -274,7 +274,7 @@ namespace Avalonia.Rendering.SceneGraph
                 }
             }
 
-            if (node.LayerRoot == node.Visual)
+            if (node.LayerRoot == node.Visual && node.Visual != scene.Root.Visual)
             {
                 scene.Layers.Remove(node.LayerRoot);
             }
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
index e65487ac44..13f28018db 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/SceneBuilderTests_Layers.cs
@@ -273,5 +273,32 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
                     ((MockStreamGeometryImpl)borderLayer.GeometryClip).Transform);
             }
         }
+
+        [Fact]
+        public void Hiding_Root_Should_Not_Remove_Root_Layer()
+        {
+            using (TestApplication())
+            {
+                Border border;
+                var tree = new TestRoot
+                {
+                    Child = border = new Border()
+                };
+
+                var layout = AvaloniaLocator.Current.GetService<ILayoutManager>();
+                layout.ExecuteInitialLayoutPass(tree);
+
+                var scene = new Scene(tree);
+                var sceneBuilder = new SceneBuilder();
+                sceneBuilder.UpdateAll(scene);
+
+                tree.IsVisible = false;
+
+                scene = scene.Clone();
+                sceneBuilder.Update(scene, tree);
+
+                Assert.Equal(1, scene.Layers.Count);
+            }
+        }
     }
 }