diff --git a/samples/ControlCatalog/Pages/DialogsPage.xaml b/samples/ControlCatalog/Pages/DialogsPage.xaml
index 1ed5c0cbfd..0834e829d8 100644
--- a/samples/ControlCatalog/Pages/DialogsPage.xaml
+++ b/samples/ControlCatalog/Pages/DialogsPage.xaml
@@ -6,6 +6,7 @@
       <Button Name="OpenFile">Open File</Button>
       <Button Name="SaveFile">Save File</Button>
       <Button Name="SelectFolder">Select Folder</Button>
+      <Button Name="OpenBoth">Select Both</Button>
       <Button Name="DecoratedWindow">Decorated window</Button>
       <Button Name="DecoratedWindowDialog">Decorated window (dialog)</Button>
       <Button Name="Dialog">Dialog</Button>
diff --git a/samples/ControlCatalog/Pages/DialogsPage.xaml.cs b/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
index ba1921a185..dcb94a89e7 100644
--- a/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
+++ b/samples/ControlCatalog/Pages/DialogsPage.xaml.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
 using Avalonia.Controls;
+using Avalonia.Dialogs;
 using Avalonia.Markup.Xaml;
 #pragma warning disable 4014
 
@@ -58,6 +59,19 @@ namespace ControlCatalog.Pages
                     Title = "Select folder",
                 }.ShowAsync(GetWindow());
             };
+            this.FindControl<Button>("OpenBoth").Click += async delegate
+            {
+                var res = await new OpenFileDialog()
+                {
+                    Title = "Select both",
+                    AllowMultiple = true
+                }.ShowManagedAsync(GetWindow(), new ManagedFileDialogOptions
+                {
+                    AllowDirectorySelection = true
+                });
+                if (res != null)
+                    Console.WriteLine("Selected: \n" + string.Join("\n", res));
+            };
             this.FindControl<Button>("DecoratedWindow").Click += delegate
             {
                 new DecoratedWindow().Show();
diff --git a/src/Avalonia.Dialogs/ManagedFileChooserViewModel.cs b/src/Avalonia.Dialogs/ManagedFileChooserViewModel.cs
index 189e13802d..1e2d15ab70 100644
--- a/src/Avalonia.Dialogs/ManagedFileChooserViewModel.cs
+++ b/src/Avalonia.Dialogs/ManagedFileChooserViewModel.cs
@@ -14,6 +14,7 @@ namespace Avalonia.Dialogs
 {
     internal class ManagedFileChooserViewModel : InternalViewModelBase
     {
+        private readonly ManagedFileDialogOptions _options;
         public event Action CancelRequested;
         public event Action<string[]> CompleteRequested;
 
@@ -103,8 +104,9 @@ namespace Avalonia.Dialogs
             QuickLinks.AddRange(quickSources.GetAllItems().Select(i => new ManagedFileChooserItemViewModel(i)));
         }
 
-        public ManagedFileChooserViewModel(FileSystemDialog dialog)
+        public ManagedFileChooserViewModel(FileSystemDialog dialog, ManagedFileDialogOptions options)
         {
+            _options = options;
             _disposables = new CompositeDisposable();
 
             var quickSources = AvaloniaLocator.Current
@@ -202,10 +204,12 @@ namespace Avalonia.Dialogs
                     }
                     else
                     {
-                        var invalidItems = SelectedItems.Where(i => i.ItemType == ManagedFileChooserItemType.Folder).ToList();
-                        foreach (var item in invalidItems)
+                        if (!_options.AllowDirectorySelection)
                         {
-                            SelectedItems.Remove(item);
+                            var invalidItems = SelectedItems.Where(i => i.ItemType == ManagedFileChooserItemType.Folder)
+                                .ToList();
+                            foreach (var item in invalidItems) 
+                                SelectedItems.Remove(item);
                         }
 
                         if (!_selectingDirectory)
diff --git a/src/Avalonia.Dialogs/ManagedFileDialogExtensions.cs b/src/Avalonia.Dialogs/ManagedFileDialogExtensions.cs
index 41f526a513..f9e62d905b 100644
--- a/src/Avalonia.Dialogs/ManagedFileDialogExtensions.cs
+++ b/src/Avalonia.Dialogs/ManagedFileDialogExtensions.cs
@@ -9,13 +9,15 @@ namespace Avalonia.Dialogs
     {
         private class ManagedSystemDialogImpl<T> : ISystemDialogImpl where T : Window, new()
         {
-            async Task<string[]> Show(SystemDialog d, Window parent)
+            async Task<string[]> Show(SystemDialog d, Window parent, ManagedFileDialogOptions options = null)
             {
-                var model = new ManagedFileChooserViewModel((FileSystemDialog)d);
+                var model = new ManagedFileChooserViewModel((FileSystemDialog)d,
+                    options ?? new ManagedFileDialogOptions());
 
                 var dialog = new T
                 {
                     Content = new ManagedFileChooser(),
+                    Title = d.Title,
                     DataContext = model
                 };
 
@@ -44,6 +46,11 @@ namespace Avalonia.Dialogs
             {
                 return (await Show(dialog, parent))?.FirstOrDefault();
             }
+            
+            public async Task<string[]> ShowFileDialogAsync(FileDialog dialog, Window parent, ManagedFileDialogOptions options)
+            {
+                return await Show(dialog, parent, options);
+            }
         }
 
         public static TAppBuilder UseManagedSystemDialogs<TAppBuilder>(this TAppBuilder builder)
@@ -61,5 +68,14 @@ namespace Avalonia.Dialogs
                 AvaloniaLocator.CurrentMutable.Bind<ISystemDialogImpl>().ToSingleton<ManagedSystemDialogImpl<TWindow>>());
             return builder;
         }
+
+        public static Task<string[]> ShowManagedAsync(this OpenFileDialog dialog, Window parent,
+            ManagedFileDialogOptions options = null) => ShowManagedAsync<Window>(dialog, parent, options);
+        
+        public static Task<string[]> ShowManagedAsync<TWindow>(this OpenFileDialog dialog, Window parent,
+            ManagedFileDialogOptions options = null) where TWindow : Window, new()
+        {
+            return new ManagedSystemDialogImpl<TWindow>().ShowFileDialogAsync(dialog, parent, options);
+        }
     }
 }
diff --git a/src/Avalonia.Dialogs/ManagedFileDialogOptions.cs b/src/Avalonia.Dialogs/ManagedFileDialogOptions.cs
new file mode 100644
index 0000000000..56a3eb9122
--- /dev/null
+++ b/src/Avalonia.Dialogs/ManagedFileDialogOptions.cs
@@ -0,0 +1,7 @@
+namespace Avalonia.Dialogs
+{
+    public class ManagedFileDialogOptions
+    {
+        public bool AllowDirectorySelection { get; set; }
+    }
+}
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/Scene.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/Scene.cs
index b4bf4c799a..0f6001516d 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/Scene.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/Scene.cs
@@ -12,7 +12,7 @@ namespace Avalonia.Rendering.SceneGraph
     /// </summary>
     public class Scene : IDisposable
     {
-        private Dictionary<IVisual, IVisualNode> _index;
+        private readonly Dictionary<IVisual, IVisualNode> _index;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="Scene"/> class.
@@ -83,7 +83,7 @@ namespace Avalonia.Rendering.SceneGraph
         /// <returns>The cloned scene.</returns>
         public Scene CloneScene()
         {
-            var index = new Dictionary<IVisual, IVisualNode>();
+            var index = new Dictionary<IVisual, IVisualNode>(_index.Count);
             var root = Clone((VisualNode)Root, null, index);
 
             var result = new Scene(root, index, Layers.Clone(), Generation + 1)
@@ -162,9 +162,19 @@ namespace Avalonia.Rendering.SceneGraph
 
             index.Add(result.Visual, result);
 
-            foreach (var child in source.Children)
+            var children = source.Children;
+            var childrenCount = children.Count;
+
+            if (childrenCount > 0)
             {
-                result.AddChild(Clone((VisualNode)child, result, index));
+                result.TryPreallocateChildren(childrenCount);
+
+                for (var i = 0; i < childrenCount; i++)
+                {
+                    var child = children[i];
+
+                    result.AddChild(Clone((VisualNode)child, result, index));
+                }
             }
 
             return result;
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneLayers.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneLayers.cs
index 5960b4f560..25f7383a1a 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/SceneLayers.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/SceneLayers.cs
@@ -11,16 +11,28 @@ namespace Avalonia.Rendering.SceneGraph
     public class SceneLayers : IEnumerable<SceneLayer>
     {
         private readonly IVisual _root;
-        private readonly List<SceneLayer> _inner = new List<SceneLayer>();
-        private readonly Dictionary<IVisual, SceneLayer> _index = new Dictionary<IVisual, SceneLayer>();
+        private readonly List<SceneLayer> _inner;
+        private readonly Dictionary<IVisual, SceneLayer> _index;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="SceneLayers"/> class.
         /// </summary>
         /// <param name="root">The scene's root visual.</param>
-        public SceneLayers(IVisual root)
+        public SceneLayers(IVisual root) : this(root, 0)
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="SceneLayers"/> class.
+        /// </summary>
+        /// <param name="root">The scene's root visual.</param>
+        /// <param name="capacity">Initial layer capacity.</param>
+        public SceneLayers(IVisual root, int capacity)
         {
             _root = root;
+
+            _inner = new List<SceneLayer>(capacity);
+            _index = new Dictionary<IVisual, SceneLayer>(capacity);
         }
 
         /// <summary>
@@ -84,7 +96,7 @@ namespace Avalonia.Rendering.SceneGraph
         /// <returns>The cloned layers.</returns>
         public SceneLayers Clone()
         {
-            var result = new SceneLayers(_root);
+            var result = new SceneLayers(_root, Count);
 
             foreach (var src in _inner)
             {
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
index 82444a0c29..6f566ff6d6 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/VisualNode.cs
@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Reactive.Disposables;
+using Avalonia.Collections;
 using Avalonia.Media;
 using Avalonia.Platform;
 using Avalonia.Utilities;
@@ -349,6 +349,11 @@ namespace Avalonia.Rendering.SceneGraph
             context.Transform = transformRestore;
         }
 
+        internal void TryPreallocateChildren(int count)
+        {
+            EnsureChildrenCreated(count);
+        }
+
         private Rect CalculateBounds()
         {
             var result = new Rect();
@@ -362,11 +367,11 @@ namespace Avalonia.Rendering.SceneGraph
             return result;
         }
 
-        private void EnsureChildrenCreated()
+        private void EnsureChildrenCreated(int capacity = 0)
         {
             if (_children == null)
             {
-                _children = new List<IVisualNode>();
+                _children = new List<IVisualNode>(capacity);
             }
         }
 
@@ -383,7 +388,15 @@ namespace Avalonia.Rendering.SceneGraph
             }
             else if (_drawOperationsCloned)
             {
-                _drawOperations = new List<IRef<IDrawOperation>>(_drawOperations.Select(op => op.Clone()));
+                var oldDrawOperations = _drawOperations;
+
+                _drawOperations = new List<IRef<IDrawOperation>>(oldDrawOperations.Count);
+
+                foreach (var drawOperation in oldDrawOperations)
+                {
+                    _drawOperations.Add(drawOperation.Clone());
+                }
+
                 _drawOperationsRefCounter.Dispose();
                 _drawOperationsRefCounter = RefCountable.Create(CreateDisposeDrawOperations(_drawOperations));
                 _drawOperationsCloned = false;
@@ -399,9 +412,9 @@ namespace Avalonia.Rendering.SceneGraph
         /// <returns>Disposable for given draw operations.</returns>
         private static IDisposable CreateDisposeDrawOperations(List<IRef<IDrawOperation>> drawOperations)
         {
-            return Disposable.Create(() =>
+            return Disposable.Create(drawOperations, operations =>
             {
-                foreach (var operation in drawOperations)
+                foreach (var operation in operations)
                 {
                     operation.Dispose();
                 }
diff --git a/src/Avalonia.X11/X11Window.cs b/src/Avalonia.X11/X11Window.cs
index 026a1457a3..0c349ce140 100644
--- a/src/Avalonia.X11/X11Window.cs
+++ b/src/Avalonia.X11/X11Window.cs
@@ -328,7 +328,9 @@ namespace Avalonia.X11
             }
             else if (ev.type == XEventName.UnmapNotify)
                 _mapped = false;
-            else if (ev.type == XEventName.Expose)
+            else if (ev.type == XEventName.Expose ||
+                     (ev.type == XEventName.VisibilityNotify &&
+                      ev.VisibilityEvent.state < 2))
             {
                 if (!_triggeredExpose)
                 {
diff --git a/src/Skia/Avalonia.Skia/PlatformRenderInterface.cs b/src/Skia/Avalonia.Skia/PlatformRenderInterface.cs
index 09b8600a9e..bfe24bb429 100644
--- a/src/Skia/Avalonia.Skia/PlatformRenderInterface.cs
+++ b/src/Skia/Avalonia.Skia/PlatformRenderInterface.cs
@@ -18,7 +18,7 @@ namespace Avalonia.Skia
 
         private GRContext GrContext { get; }
 
-        public PlatformRenderInterface(ICustomSkiaGpu customSkiaGpu, long maxResourceBytes = 100000000)
+        public PlatformRenderInterface(ICustomSkiaGpu customSkiaGpu, long maxResourceBytes = 100663296)
         {
             if (customSkiaGpu != null)
             {
diff --git a/src/Skia/Avalonia.Skia/SkiaOptions.cs b/src/Skia/Avalonia.Skia/SkiaOptions.cs
index b180466c4e..2d5e5990e6 100644
--- a/src/Skia/Avalonia.Skia/SkiaOptions.cs
+++ b/src/Skia/Avalonia.Skia/SkiaOptions.cs
@@ -10,7 +10,7 @@ namespace Avalonia
     {
         public SkiaOptions()
         {
-            MaxGpuResourceSizeBytes = 512000000;
+            MaxGpuResourceSizeBytes = 100663296; // Value taken from skia.
         }
         /// <summary>
         /// Custom gpu factory to use. Can be used to customize behavior of Skia renderer.