diff --git a/samples/BindingDemo/ViewModels/ExceptionErrorViewModel.cs b/samples/BindingDemo/ViewModels/ExceptionErrorViewModel.cs
index 2ab6c26e68..df80931367 100644
--- a/samples/BindingDemo/ViewModels/ExceptionErrorViewModel.cs
+++ b/samples/BindingDemo/ViewModels/ExceptionErrorViewModel.cs
@@ -21,7 +21,7 @@ namespace BindingDemo.ViewModels
                 }
                 else
                 {
-                    throw new ArgumentOutOfRangeException("Value must be less than 10.");
+                    throw new ArgumentOutOfRangeException(nameof(value), "Value must be less than 10.");
                 }
             }
         }
diff --git a/samples/ControlCatalog/SideBar.xaml b/samples/ControlCatalog/SideBar.xaml
index 625b344b8c..fea55bcb07 100644
--- a/samples/ControlCatalog/SideBar.xaml
+++ b/samples/ControlCatalog/SideBar.xaml
@@ -1,6 +1,14 @@
 <Styles xmlns="https://github.com/avaloniaui"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         x:Class="ControlCatalog.SideBar">
+    <Design.PreviewWith>
+        <Border Padding="20">
+            <TabControl Classes="sidebar">
+                <TabItem Header="Item1"/>
+                <TabItem Header="Item2"/>
+            </TabControl> 
+        </Border>
+    </Design.PreviewWith>
     <Style Selector="TabControl.sidebar">
         <Setter Property="TabStripPlacement" Value="Left"/>
         <Setter Property="Padding" Value="8 0 0 0"/>
diff --git a/src/Avalonia.Base/Data/Core/Plugins/MethodAccessorPlugin.cs b/src/Avalonia.Base/Data/Core/Plugins/MethodAccessorPlugin.cs
index 135935498c..e48c671a13 100644
--- a/src/Avalonia.Base/Data/Core/Plugins/MethodAccessorPlugin.cs
+++ b/src/Avalonia.Base/Data/Core/Plugins/MethodAccessorPlugin.cs
@@ -21,7 +21,7 @@ namespace Avalonia.Data.Core.Plugins
             {
                 if (method.GetParameters().Length + (method.ReturnType == typeof(void) ? 0 : 1) > 8)
                 {
-                    var exception = new ArgumentException("Cannot create a binding accessor for a method with more than 8 parameters or more than 7 parameters if it has a non-void return type.", nameof(method));
+                    var exception = new ArgumentException("Cannot create a binding accessor for a method with more than 8 parameters or more than 7 parameters if it has a non-void return type.", nameof(methodName));
                     return new PropertyError(new BindingNotification(exception, BindingErrorType.Error));
                 }
 
diff --git a/src/Avalonia.Controls/Design.cs b/src/Avalonia.Controls/Design.cs
index 894240a09f..0d05e19e53 100644
--- a/src/Avalonia.Controls/Design.cs
+++ b/src/Avalonia.Controls/Design.cs
@@ -48,14 +48,14 @@ namespace Avalonia.Controls
         }
         
         public static readonly AttachedProperty<Control> PreviewWithProperty = AvaloniaProperty
-            .RegisterAttached<Style, Control>("PreviewWith", typeof (Design));
+            .RegisterAttached<AvaloniaObject, Control>("PreviewWith", typeof (Design));
 
-        public static void SetPreviewWith(Style target, Control control)
+        public static void SetPreviewWith(AvaloniaObject target, Control control)
         {
             target.SetValue(PreviewWithProperty, control);
         }
 
-        public static Control GetPreviewWith(Style target)
+        public static Control GetPreviewWith(AvaloniaObject target)
         {
             return target.GetValue(PreviewWithProperty);
         }
diff --git a/src/Avalonia.Controls/Embedding/Offscreen/OffscreenTopLevelImpl.cs b/src/Avalonia.Controls/Embedding/Offscreen/OffscreenTopLevelImpl.cs
index d328e1ee88..9c53dc0c10 100644
--- a/src/Avalonia.Controls/Embedding/Offscreen/OffscreenTopLevelImpl.cs
+++ b/src/Avalonia.Controls/Embedding/Offscreen/OffscreenTopLevelImpl.cs
@@ -11,11 +11,13 @@ namespace Avalonia.Controls.Embedding.Offscreen
     {
         private double _scaling = 1;
         private Size _clientSize;
+
         public IInputRoot InputRoot { get; private set; }
+        public bool IsDisposed { get; private set; }
 
         public virtual void Dispose()
         {
-            //No-op
+            IsDisposed = true;
         }
 
         public IRenderer CreateRenderer(IRenderRoot root) => new ImmediateRenderer(root);
diff --git a/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs b/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
index 18cef7d64e..f8ae5c9690 100644
--- a/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
+++ b/src/Avalonia.Controls/NumericUpDown/NumericUpDown.cs
@@ -965,11 +965,11 @@ namespace Avalonia.Controls
         {
             if (value < Minimum)
             {
-                throw new ArgumentOutOfRangeException(nameof(Minimum), string.Format("Value must be greater than Minimum value of {0}", Minimum));
+                throw new ArgumentOutOfRangeException(nameof(value), string.Format("Value must be greater than Minimum value of {0}", Minimum));
             }
             else if (value > Maximum)
             {
-                throw new ArgumentOutOfRangeException(nameof(Maximum), string.Format("Value must be less than Maximum value of {0}", Maximum));
+                throw new ArgumentOutOfRangeException(nameof(value), string.Format("Value must be less than Maximum value of {0}", Maximum));
             }
         }
 
diff --git a/src/Avalonia.Controls/Remote/Server/RemoteServerTopLevelImpl.cs b/src/Avalonia.Controls/Remote/Server/RemoteServerTopLevelImpl.cs
index e1767fca36..6293cbfbfd 100644
--- a/src/Avalonia.Controls/Remote/Server/RemoteServerTopLevelImpl.cs
+++ b/src/Avalonia.Controls/Remote/Server/RemoteServerTopLevelImpl.cs
@@ -61,6 +61,11 @@ namespace Avalonia.Controls.Remote.Server
         {
             var result = InputModifiers.None;
 
+            if (modifiers == null)
+            {
+                return result;
+            }
+
             foreach(var modifier in modifiers)
             {
                 switch (modifier)
@@ -265,11 +270,15 @@ namespace Avalonia.Controls.Remote.Server
             var bpp = fmt == ProtocolPixelFormat.Rgb565 ? 2 : 4;
             var data = new byte[width * height * bpp];
             var handle = GCHandle.Alloc(data, GCHandleType.Pinned);
+
             try
             {
-                _framebuffer = new LockedFramebuffer(handle.AddrOfPinnedObject(), new PixelSize(width, height), width * bpp, _dpi, (PixelFormat)fmt,
-                    null);
-                Paint?.Invoke(new Rect(0, 0, width, height));
+                if (width > 0 && height > 0)
+                {
+                    _framebuffer = new LockedFramebuffer(handle.AddrOfPinnedObject(), new PixelSize(width, height), width * bpp, _dpi, (PixelFormat)fmt,
+                        null);
+                    Paint?.Invoke(new Rect(0, 0, width, height));
+                }
             }
             finally
             {
@@ -301,8 +310,7 @@ namespace Avalonia.Controls.Remote.Server
                     return;
 
             }
-            if (ClientSize.Width < 1 || ClientSize.Height < 1)
-                return;
+
             var format = ProtocolPixelFormat.Rgba8888;
             foreach(var fmt in _supportedFormats)
                 if (fmt <= ProtocolPixelFormat.MaxValue)
@@ -323,8 +331,11 @@ namespace Avalonia.Controls.Remote.Server
 
         public override void Invalidate(Rect rect)
         {
-            _invalidated = true;
-            Dispatcher.UIThread.Post(RenderIfNeeded);
+            if (!IsDisposed)
+            {
+                _invalidated = true;
+                Dispatcher.UIThread.Post(RenderIfNeeded);
+            }
         }
 
         public override IMouseDevice MouseDevice { get; } = new MouseDevice();
diff --git a/src/Avalonia.Controls/Shapes/Shape.cs b/src/Avalonia.Controls/Shapes/Shape.cs
index 0387328a46..57dbeba1cc 100644
--- a/src/Avalonia.Controls/Shapes/Shape.cs
+++ b/src/Avalonia.Controls/Shapes/Shape.cs
@@ -195,7 +195,7 @@ namespace Avalonia.Controls.Shapes
             if (deferCalculateTransform)
             {
                 _calculateTransformOnArrange = true;
-                return DefiningGeometry.Bounds.Size;
+                return DefiningGeometry?.Bounds.Size ?? Size.Empty;
             }
             else
             {
@@ -217,17 +217,22 @@ namespace Avalonia.Controls.Shapes
 
         private Size CalculateShapeSizeAndSetTransform(Size availableSize)
         {
-            // This should probably use GetRenderBounds(strokeThickness) but then the calculations
-            // will multiply the stroke thickness as well, which isn't correct.
-            var (size, transform) = CalculateSizeAndTransform(availableSize, DefiningGeometry.Bounds, Stretch);
-
-            if (_transform != transform)
+            if (DefiningGeometry != null)
             {
-                _transform = transform;
-                _renderedGeometry = null;
+                // This should probably use GetRenderBounds(strokeThickness) but then the calculations
+                // will multiply the stroke thickness as well, which isn't correct.
+                var (size, transform) = CalculateSizeAndTransform(availableSize, DefiningGeometry.Bounds, Stretch);
+
+                if (_transform != transform)
+                {
+                    _transform = transform;
+                    _renderedGeometry = null;
+                }
+
+                return size;
             }
 
-            return size;
+            return Size.Empty;
         }
 
         internal static (Size, Matrix) CalculateSizeAndTransform(Size availableSize, Rect shapeBounds, Stretch Stretch)
diff --git a/src/Avalonia.DesignerSupport/DesignWindowLoader.cs b/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
index 8fee31408f..a7d4b96974 100644
--- a/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
+++ b/src/Avalonia.DesignerSupport/DesignWindowLoader.cs
@@ -35,13 +35,13 @@ namespace Avalonia.DesignerSupport
 
                 var localAsm = assemblyPath != null ? Assembly.LoadFile(Path.GetFullPath(assemblyPath)) : null;
                 var loaded = loader.Load(stream, localAsm, null, baseUri);
-                var styles = loaded as Styles;
-                if (styles != null)
+                var style = loaded as IStyle;
+                if (style != null)
                 {
-                    var substitute = styles.OfType<Style>().Select(Design.GetPreviewWith).FirstOrDefault(s => s != null);
+                    var substitute = Design.GetPreviewWith((AvaloniaObject)style);
                     if (substitute != null)
                     {
-                        substitute.Styles.AddRange(styles);
+                        substitute.Styles.Add(style);
                         control = substitute;
                     }
                     else
@@ -51,8 +51,8 @@ namespace Avalonia.DesignerSupport
                             {
                                 new TextBlock {Text = "Styles can't be previewed without Design.PreviewWith. Add"},
                                 new TextBlock {Text = "<Design.PreviewWith>"},
-                                new TextBlock {Text = "    <Border Padding=20><!-- YOUR CONTROL FOR PREVIEW HERE--></Border>"},
-                                new TextBlock {Text = "<Design.PreviewWith>"},
+                                new TextBlock {Text = "    <Border Padding=20><!-- YOUR CONTROL FOR PREVIEW HERE --></Border>"},
+                                new TextBlock {Text = "</Design.PreviewWith>"},
                                 new TextBlock {Text = "before setters in your first Style"}
                             }
                         };
diff --git a/src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs b/src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs
index 09196e4fb7..67a93f3c9c 100644
--- a/src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs
+++ b/src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs
@@ -8,6 +8,7 @@ using Avalonia.Remote.Protocol;
 using Avalonia.Remote.Protocol.Designer;
 using Avalonia.Remote.Protocol.Viewport;
 using Avalonia.Threading;
+using Portable.Xaml;
 
 namespace Avalonia.DesignerSupport.Remote
 {
@@ -204,9 +205,18 @@ namespace Avalonia.DesignerSupport.Remote
                 }
                 catch (Exception e)
                 {
+                    var xamlException = e as XamlException;
+
                     s_transport.Send(new UpdateXamlResultMessage
                     {
-                        Error = e.ToString()
+                        Error = e.ToString(),
+                        Exception = new ExceptionDetails
+                        {
+                            ExceptionType = e.GetType().FullName,
+                            Message = e.Message.ToString(),
+                            LineNumber = xamlException?.LineNumber,
+                            LinePosition = xamlException?.LinePosition,
+                        }
                     });
                 }
             }
diff --git a/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj b/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
index 871c9cd995..6684772bfe 100644
--- a/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
+++ b/src/Avalonia.Remote.Protocol/Avalonia.Remote.Protocol.csproj
@@ -2,6 +2,8 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <DefineConstants>AVALONIA_REMOTE_PROTOCOL;$(DefineConstants)</DefineConstants>
+    <SignAssembly>true</SignAssembly>
+    <AssemblyOriginatorKeyFile>Key.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="..\Avalonia.Input\Key.cs" />
diff --git a/src/Avalonia.Remote.Protocol/DesignMessages.cs b/src/Avalonia.Remote.Protocol/DesignMessages.cs
index f70bcef6b3..5ff16c574d 100644
--- a/src/Avalonia.Remote.Protocol/DesignMessages.cs
+++ b/src/Avalonia.Remote.Protocol/DesignMessages.cs
@@ -15,6 +15,7 @@ namespace Avalonia.Remote.Protocol.Designer
     {
         public string Error { get; set; }
         public string Handle { get; set; }
+        public ExceptionDetails Exception { get; set; }
     }
 
     [AvaloniaRemoteMessageGuid("854887CF-2694-4EB6-B499-7461B6FB96C7")]
@@ -23,4 +24,11 @@ namespace Avalonia.Remote.Protocol.Designer
         public string SessionId { get; set; }
     }
     
+    public class ExceptionDetails
+    {
+        public string ExceptionType { get; set; }
+        public string Message { get; set; }
+        public int? LineNumber { get; set; }
+        public int? LinePosition { get; set; }
+    }
 }
diff --git a/src/Avalonia.Remote.Protocol/Key.snk b/src/Avalonia.Remote.Protocol/Key.snk
new file mode 100644
index 0000000000..d6cbc36f52
Binary files /dev/null and b/src/Avalonia.Remote.Protocol/Key.snk differ
diff --git a/src/Avalonia.Remote.Protocol/MetsysBson.cs b/src/Avalonia.Remote.Protocol/MetsysBson.cs
index 925fe10681..5593112bd6 100644
--- a/src/Avalonia.Remote.Protocol/MetsysBson.cs
+++ b/src/Avalonia.Remote.Protocol/MetsysBson.cs
@@ -749,7 +749,7 @@ namespace Metsys.Bson
 
                         if (memberExpression.Expression.NodeType != ExpressionType.Parameter && memberExpression.Expression.NodeType != ExpressionType.Convert)
                         {
-                            throw new ArgumentException(string.Format("Expression '{0}' must resolve to top-level member.", lambdaExpression), "lambdaExpression");
+                            throw new ArgumentException(string.Format("Expression '{0}' must resolve to top-level member.", lambdaExpression), nameof(lambdaExpression));
                         }
                         return memberExpression.Member.Name;
                     default:
diff --git a/src/Avalonia.Styling/Styling/Styles.cs b/src/Avalonia.Styling/Styling/Styles.cs
index 51499b737a..288cf35d08 100644
--- a/src/Avalonia.Styling/Styling/Styles.cs
+++ b/src/Avalonia.Styling/Styling/Styles.cs
@@ -2,7 +2,9 @@
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
 using System;
+using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Linq;
 using Avalonia.Collections;
 using Avalonia.Controls;
@@ -12,16 +14,17 @@ namespace Avalonia.Styling
     /// <summary>
     /// A style that consists of a number of child styles.
     /// </summary>
-    public class Styles : AvaloniaList<IStyle>, IStyle, ISetStyleParent
+    public class Styles : AvaloniaObject, IAvaloniaList<IStyle>, IStyle, ISetStyleParent
     {
         private IResourceNode _parent;
         private IResourceDictionary _resources;
+        private AvaloniaList<IStyle> _styles = new AvaloniaList<IStyle>();
         private Dictionary<Type, List<IStyle>> _cache;
 
         public Styles()
         {
-            ResetBehavior = ResetBehavior.Remove;
-            this.ForEachItem(
+            _styles.ResetBehavior = ResetBehavior.Remove;
+            _styles.ForEachItem(
                 x =>
                 {
                     if (x.ResourceParent == null && x is ISetStyleParent setParent)
@@ -57,9 +60,18 @@ namespace Avalonia.Styling
                 () => { });
         }
 
+        public event NotifyCollectionChangedEventHandler CollectionChanged
+        {
+            add => _styles.CollectionChanged += value;
+            remove => _styles.CollectionChanged -= value;
+        }
+
         /// <inheritdoc/>
         public event EventHandler<ResourcesChangedEventArgs> ResourcesChanged;
 
+        /// <inheritdoc/>
+        public int Count => _styles.Count;
+
         /// <inheritdoc/>
         public bool HasResources => _resources?.Count > 0 || this.Any(x => x.HasResources);
 
@@ -94,6 +106,19 @@ namespace Avalonia.Styling
         /// <inheritdoc/>
         IResourceNode IResourceNode.ResourceParent => _parent;
 
+        /// <inheritdoc/>
+        bool ICollection<IStyle>.IsReadOnly => false;
+
+        /// <inheritdoc/>
+        IStyle IReadOnlyList<IStyle>.this[int index] => _styles[index];
+
+        /// <inheritdoc/>
+        public IStyle this[int index]
+        {
+            get => _styles[index];
+            set => _styles[index] = value;
+        }
+
         /// <summary>
         /// Attaches the style to a control if the style's selector matches.
         /// </summary>
@@ -172,6 +197,54 @@ namespace Avalonia.Styling
             return false;
         }
 
+        /// <inheritdoc/>
+        public void AddRange(IEnumerable<IStyle> items) => _styles.AddRange(items);
+
+        /// <inheritdoc/>
+        public void InsertRange(int index, IEnumerable<IStyle> items) => _styles.InsertRange(index, items);
+
+        /// <inheritdoc/>
+        public void Move(int oldIndex, int newIndex) => _styles.Move(oldIndex, newIndex);
+
+        /// <inheritdoc/>
+        public void MoveRange(int oldIndex, int count, int newIndex) => _styles.MoveRange(oldIndex, count, newIndex);
+
+        /// <inheritdoc/>
+        public void RemoveAll(IEnumerable<IStyle> items) => _styles.RemoveAll(items);
+
+        /// <inheritdoc/>
+        public void RemoveRange(int index, int count) => _styles.RemoveRange(index, count);
+
+        /// <inheritdoc/>
+        public int IndexOf(IStyle item) => _styles.IndexOf(item);
+
+        /// <inheritdoc/>
+        public void Insert(int index, IStyle item) => _styles.Insert(index, item);
+
+        /// <inheritdoc/>
+        public void RemoveAt(int index) => _styles.RemoveAt(index);
+
+        /// <inheritdoc/>
+        public void Add(IStyle item) => _styles.Add(item);
+
+        /// <inheritdoc/>
+        public void Clear() => _styles.Clear();
+
+        /// <inheritdoc/>
+        public bool Contains(IStyle item) => _styles.Contains(item);
+
+        /// <inheritdoc/>
+        public void CopyTo(IStyle[] array, int arrayIndex) => _styles.CopyTo(array, arrayIndex);
+
+        /// <inheritdoc/>
+        public bool Remove(IStyle item) => _styles.Remove(item);
+
+        /// <inheritdoc/>
+        public IEnumerator<IStyle> GetEnumerator() => _styles.GetEnumerator();
+
+        /// <inheritdoc/>
+        IEnumerator IEnumerable.GetEnumerator() => _styles.GetEnumerator();
+
         /// <inheritdoc/>
         void ISetStyleParent.SetParent(IResourceNode parent)
         {
diff --git a/src/Avalonia.Visuals/Media/DrawingContext.cs b/src/Avalonia.Visuals/Media/DrawingContext.cs
index e7d6df5a93..fd593db991 100644
--- a/src/Avalonia.Visuals/Media/DrawingContext.cs
+++ b/src/Avalonia.Visuals/Media/DrawingContext.cs
@@ -109,6 +109,8 @@ namespace Avalonia.Media
         /// <param name="geometry">The geometry.</param>
         public void DrawGeometry(IBrush brush, Pen pen, Geometry geometry)
         {
+            Contract.Requires<ArgumentNullException>(geometry != null);
+
             if (brush != null || PenIsVisible(pen))
             {
                 PlatformImpl.DrawGeometry(brush, pen, geometry.PlatformImpl);
diff --git a/src/Avalonia.Visuals/Media/GeometryDrawing.cs b/src/Avalonia.Visuals/Media/GeometryDrawing.cs
index a26a5341c8..ac0cc1c17d 100644
--- a/src/Avalonia.Visuals/Media/GeometryDrawing.cs
+++ b/src/Avalonia.Visuals/Media/GeometryDrawing.cs
@@ -31,7 +31,10 @@
 
         public override void Draw(DrawingContext context)
         {
-            context.DrawGeometry(Brush, Pen, Geometry);
+            if (Geometry != null)
+            {
+                context.DrawGeometry(Brush, Pen, Geometry);
+            }
         }
 
         public override Rect GetBounds()
@@ -41,4 +44,4 @@
             return Geometry?.GetRenderBounds(pen) ?? new Rect();
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Avalonia.Visuals/Rendering/SceneGraph/GeometryNode.cs b/src/Avalonia.Visuals/Rendering/SceneGraph/GeometryNode.cs
index 46d264e518..2d01b117d9 100644
--- a/src/Avalonia.Visuals/Rendering/SceneGraph/GeometryNode.cs
+++ b/src/Avalonia.Visuals/Rendering/SceneGraph/GeometryNode.cs
@@ -89,9 +89,14 @@ namespace Avalonia.Rendering.SceneGraph
         /// <inheritdoc/>
         public override bool HitTest(Point p)
         {
-            p *= Transform.Invert();
-            return (Brush != null && Geometry.FillContains(p)) || 
-                (Pen != null && Geometry.StrokeContains(Pen, p));
+            if (Transform.HasInverse)
+            {
+                p *= Transform.Invert();
+                return (Brush != null && Geometry.FillContains(p)) ||
+                    (Pen != null && Geometry.StrokeContains(Pen, p));
+            }
+
+            return false;
         }
     }
 }
diff --git a/src/Avalonia.Visuals/Visual.cs b/src/Avalonia.Visuals/Visual.cs
index bf282db72f..ab2f5307a0 100644
--- a/src/Avalonia.Visuals/Visual.cs
+++ b/src/Avalonia.Visuals/Visual.cs
@@ -551,7 +551,7 @@ namespace Avalonia
         {
             if (c == null)
             {
-                throw new ArgumentNullException("Cannot add null to VisualChildren.");
+                throw new ArgumentNullException(nameof(c), "Cannot add null to VisualChildren.");
             }
 
             if (c.VisualParent != null)
diff --git a/src/Gtk/Avalonia.Gtk3/ImageSurfaceFramebuffer.cs b/src/Gtk/Avalonia.Gtk3/ImageSurfaceFramebuffer.cs
index 44d887241c..878689442d 100644
--- a/src/Gtk/Avalonia.Gtk3/ImageSurfaceFramebuffer.cs
+++ b/src/Gtk/Avalonia.Gtk3/ImageSurfaceFramebuffer.cs
@@ -84,7 +84,7 @@ namespace Avalonia.Gtk3
             public RenderOp(GtkWidget widget, ManagedCairoSurface surface, double factor, int width, int height)
             {
                 _widget = widget;
-                _surface = surface ?? throw new ArgumentNullException();
+                _surface = surface ?? throw new ArgumentNullException(nameof(surface));
                 _factor = factor;
                 _width = width;
                 _height = height;
diff --git a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
index 38d207a31d..3c1ef84c54 100644
--- a/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
+++ b/src/Markup/Avalonia.Markup.Xaml/Avalonia.Markup.Xaml.csproj
@@ -9,6 +9,7 @@
     <ItemGroup>
         <Compile Include="AvaloniaXamlLoader.cs" />
         <Compile Include="Converters\AvaloniaUriTypeConverter.cs" />
+        <Compile Include="Converters\AvaloniaEventConverter.cs" />
         <Compile Include="Converters\FontFamilyTypeConverter.cs" />
         <Compile Include="Converters\MemberSelectorTypeConverter.cs" />
         <Compile Include="Converters\NullableTypeConverter.cs" />
diff --git a/src/Markup/Avalonia.Markup.Xaml/AvaloniaTypeConverters.cs b/src/Markup/Avalonia.Markup.Xaml/AvaloniaTypeConverters.cs
index c30822aacb..be92b6a8d7 100644
--- a/src/Markup/Avalonia.Markup.Xaml/AvaloniaTypeConverters.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/AvaloniaTypeConverters.cs
@@ -11,6 +11,7 @@ using Avalonia.Controls.Templates;
 
 namespace Avalonia.Markup.Xaml
 {
+    using System.Reflection;
     using Avalonia.Media;
 
     /// <summary>
@@ -41,7 +42,8 @@ namespace Avalonia.Markup.Xaml
             { typeof(WindowIcon), typeof(IconTypeConverter) },
             { typeof(CultureInfo), typeof(CultureInfoConverter) },
             { typeof(Uri), typeof(AvaloniaUriTypeConverter) },
-            { typeof(FontFamily), typeof(FontFamilyTypeConverter) }
+            { typeof(FontFamily), typeof(FontFamilyTypeConverter) },
+            { typeof(EventInfo), typeof(AvaloniaEventConverter) },
         };
 
         internal static Type GetBuiltinTypeConverter(Type type)
diff --git a/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoader.cs b/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoader.cs
index b99864b050..a1f8bf6cf6 100644
--- a/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoader.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/AvaloniaXamlLoader.cs
@@ -1,21 +1,20 @@
 // Copyright (c) The Avalonia Project. All rights reserved.
 // Licensed under the MIT license. See licence.md file in the project root for full license information.
 
-using Avalonia.Controls;
-using Avalonia.Markup.Data;
-using Avalonia.Markup.Xaml.PortableXaml;
-using Avalonia.Platform;
-using Portable.Xaml;
 using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Runtime.Serialization;
-using System.Runtime.Serialization.Json;
 using System.Text;
 using System.Xml.Linq;
-using System.Linq;
+using Avalonia.Controls;
+using Avalonia.Markup.Data;
+using Avalonia.Markup.Xaml.PortableXaml;
+using Avalonia.Platform;
+using Portable.Xaml;
 
 namespace Avalonia.Markup.Xaml
 {
@@ -24,29 +23,7 @@ namespace Avalonia.Markup.Xaml
     /// </summary>
     public class AvaloniaXamlLoader
     {
-        private readonly AvaloniaXamlSchemaContext _context = GetContext();
-
-        public bool IsDesignMode
-        {
-            get => _context.IsDesignMode;
-            set => _context.IsDesignMode = value;
-        }
-
-        private static AvaloniaXamlSchemaContext GetContext()
-        {
-            var result = AvaloniaLocator.Current.GetService<AvaloniaXamlSchemaContext>();
-
-            if (result == null)
-            {
-                result = AvaloniaXamlSchemaContext.Create();
-
-                AvaloniaLocator.CurrentMutable
-                    .Bind<AvaloniaXamlSchemaContext>()
-                    .ToConstant(result);
-            }
-
-            return result;
-        }
+        public bool IsDesignMode { get; set; }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="AvaloniaXamlLoader"/> class.
@@ -188,7 +165,8 @@ namespace Avalonia.Markup.Xaml
                 LocalAssembly = localAssembly
             };
 
-            var reader = new XamlXmlReader(stream, _context, readerSettings);
+            var context = IsDesignMode ? AvaloniaXamlSchemaContext.DesignInstance : AvaloniaXamlSchemaContext.Instance;
+            var reader = new XamlXmlReader(stream, context, readerSettings);
 
             object result = LoadFromReader(
                 reader,
diff --git a/src/Markup/Avalonia.Markup.Xaml/Converters/AvaloniaEventConverter.cs b/src/Markup/Avalonia.Markup.Xaml/Converters/AvaloniaEventConverter.cs
new file mode 100644
index 0000000000..665e71bfea
--- /dev/null
+++ b/src/Markup/Avalonia.Markup.Xaml/Converters/AvaloniaEventConverter.cs
@@ -0,0 +1,99 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+using System.Linq;
+using System.Linq.Expressions;
+using System.Reflection;
+using Avalonia.Controls;
+using Avalonia.Markup.Xaml.PortableXaml;
+using Portable.Xaml;
+
+namespace Avalonia.Markup.Xaml.Converters
+{
+    internal class AvaloniaEventConverter : TypeConverter
+    {
+        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+        {
+            return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
+        }
+
+        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
+        {
+            var text = value as string;
+            if (text != null)
+            {
+                var rootObjectProvider = context.GetService(typeof(IRootObjectProvider)) as IRootObjectProvider;
+                var destinationTypeProvider = context.GetService(typeof(IDestinationTypeProvider)) as IDestinationTypeProvider;
+                if (rootObjectProvider != null && destinationTypeProvider != null)
+                {
+                    var target = rootObjectProvider.RootObject;
+                    var eventType = destinationTypeProvider.GetDestinationType();
+                    var eventParameters = eventType.GetRuntimeMethods().First(r => r.Name == "Invoke").GetParameters();
+                    // go in reverse to match System.Xaml behaviour
+                    var methods = target.GetType().GetRuntimeMethods().Reverse();
+
+                    // find based on exact match parameter types first
+                    foreach (var method in methods)
+                    {
+                        if (method.Name != text)
+                            continue;
+                        var parameters = method.GetParameters();
+                        if (eventParameters.Length != parameters.Length)
+                            continue;
+                        if (parameters.Length == 0)
+                            return method.CreateDelegate(eventType, target);
+
+                        for (int i = 0; i < parameters.Length; i++)
+                        {
+                            var param = parameters[i];
+                            var eventParam = eventParameters[i];
+                            if (param.ParameterType != eventParam.ParameterType)
+                                break;
+                            if (i == parameters.Length - 1)
+                                return method.CreateDelegate(eventType, target);
+                        }
+                    }
+
+                    // EnhancedXaml: Find method with compatible base class parameters
+                    foreach (var method in methods)
+                    {
+                        if (method.Name != text)
+                            continue;
+                        var parameters = method.GetParameters();
+                        if (parameters.Length == 0 || eventParameters.Length != parameters.Length)
+                            continue;
+
+                        for (int i = 0; i < parameters.Length; i++)
+                        {
+                            var param = parameters[i];
+                            var eventParam = eventParameters[i];
+                            if (!param.ParameterType.GetTypeInfo().IsAssignableFrom(eventParam.ParameterType.GetTypeInfo()))
+                                break;
+                            if (i == parameters.Length - 1)
+                                return method.CreateDelegate(eventType, target);
+                        }
+                    }
+
+                    var contextProvider = (IXamlSchemaContextProvider)context.GetService(typeof(IXamlSchemaContextProvider));
+                    var avaloniaContext = (AvaloniaXamlSchemaContext)contextProvider.SchemaContext;
+
+                    if (avaloniaContext.IsDesignMode)
+                    {
+                        // We want to ignore missing events in the designer, so if event handler
+                        // wasn't found create an empty delegate.
+                        var lambdaExpression = Expression.Lambda(
+                            eventType,
+                            Expression.Empty(),
+                            eventParameters.Select(x => Expression.Parameter(x.ParameterType)));
+                        return lambdaExpression.Compile();
+                    }
+                    else
+                    {
+                        throw new XamlObjectWriterException($"Referenced value method {text} in type {target.GetType()} indicated by event {eventType.FullName} was not found");
+                    }
+                }
+            }
+            return base.ConvertFrom(context, culture, value);
+        }
+    }
+}
diff --git a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaMemberAttributeProvider.cs b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaMemberAttributeProvider.cs
index e9f6ba6945..529cbab938 100644
--- a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaMemberAttributeProvider.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaMemberAttributeProvider.cs
@@ -49,6 +49,18 @@ namespace Avalonia.Markup.Xaml.PortableXaml
                 //Portable.Xaml is not searching for Type Converter
                 result = new TypeConverterAttribute(typeof(SetterValueTypeConverter));
             }
+            else if (attributeType == typeof(TypeConverterAttribute) && _info is EventInfo)
+            {
+                // If a type converter for `EventInfo` is registered, then use that to convert
+                // event handler values. This is used by the designer to override the lookup
+                // for event handlers with a null handler.
+                var eventConverter = AvaloniaTypeConverters.GetTypeConverter(typeof(EventInfo));
+
+                if (eventConverter != null)
+                {
+                    result = new TypeConverterAttribute(eventConverter);
+                }
+            }
 
             if (result == null)
             {
@@ -68,4 +80,4 @@ namespace Avalonia.Markup.Xaml.PortableXaml
 
         private readonly MemberInfo _info;
     }
-}
\ No newline at end of file
+}
diff --git a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlSchemaContext.cs b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlSchemaContext.cs
index 9a493a85c0..326db884a6 100644
--- a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlSchemaContext.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlSchemaContext.cs
@@ -1,21 +1,48 @@
-using Avalonia.Data;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Avalonia.Data;
 using Avalonia.Markup.Xaml.Context;
-using Avalonia.Markup.Data;
 using Avalonia.Markup.Xaml.MarkupExtensions;
 using Avalonia.Markup.Xaml.Styling;
 using Portable.Xaml;
-using Portable.Xaml.ComponentModel;
-using System.ComponentModel;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Reflection;
 
 namespace Avalonia.Markup.Xaml.PortableXaml
 {
     internal class AvaloniaXamlSchemaContext : XamlSchemaContext
     {
-        public bool IsDesignMode { get; set; }
+        private static AvaloniaXamlSchemaContext s_instance;
+        private static AvaloniaXamlSchemaContext s_designInstance;
+
+        public static AvaloniaXamlSchemaContext Instance
+        {
+            get
+            {
+                if (s_instance == null)
+                {
+                    s_instance = Create();
+                }
+
+                return s_instance;
+            }
+        }
+
+        public static AvaloniaXamlSchemaContext DesignInstance
+        {
+            get
+            {
+                if (s_designInstance == null)
+                {
+                    s_designInstance = Create();
+                    s_designInstance.IsDesignMode = true;
+                }
+
+                return s_designInstance;
+            }
+        }
+
+        public bool IsDesignMode { get; private set; }
         public static AvaloniaXamlSchemaContext Create(IRuntimeTypeProvider typeProvider = null)
         {
             return new AvaloniaXamlSchemaContext(typeProvider ?? new AvaloniaRuntimeTypeProvider());
diff --git a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlType.cs b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlType.cs
index 2194223cb7..10cf716912 100644
--- a/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlType.cs
+++ b/src/Markup/Avalonia.Markup.Xaml/PortableXaml/AvaloniaXamlType.cs
@@ -385,4 +385,4 @@ namespace Avalonia.Markup.Xaml.PortableXaml
         {
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Markup/Avalonia.Markup/Data/RelativeSource.cs b/src/Markup/Avalonia.Markup/Data/RelativeSource.cs
index 369bd8112c..ac974e3bda 100644
--- a/src/Markup/Avalonia.Markup/Data/RelativeSource.cs
+++ b/src/Markup/Avalonia.Markup/Data/RelativeSource.cs
@@ -85,9 +85,9 @@ namespace Avalonia.Data
             get { return _ancestorLevel; }
             set
             {
-                if (_ancestorLevel <= 0)
+                if (value <= 0)
                 {
-                    throw new ArgumentOutOfRangeException("AncestorLevel may not be set to less than 1.");
+                    throw new ArgumentOutOfRangeException(nameof(value), "AncestorLevel may not be set to less than 1.");
                 }
 
                 _ancestorLevel = value;
diff --git a/tests/Avalonia.Controls.UnitTests/Shapes/PathTests.cs b/tests/Avalonia.Controls.UnitTests/Shapes/PathTests.cs
new file mode 100644
index 0000000000..05224c2495
--- /dev/null
+++ b/tests/Avalonia.Controls.UnitTests/Shapes/PathTests.cs
@@ -0,0 +1,16 @@
+using Avalonia.Controls.Shapes;
+using Xunit;
+
+namespace Avalonia.Controls.UnitTests.Shapes
+{
+    public class PathTests
+    {
+        [Fact]
+        public void Path_With_Null_Data_Does_Not_Throw_On_Measure()
+        {
+            var target = new Path();
+
+            target.Measure(Size.Infinity);
+        }
+    }
+}
diff --git a/tests/Avalonia.DesignerSupport.Tests/RemoteProtocolTests.cs b/tests/Avalonia.DesignerSupport.Tests/RemoteProtocolTests.cs
index e5a477cc32..4264559ab6 100644
--- a/tests/Avalonia.DesignerSupport.Tests/RemoteProtocolTests.cs
+++ b/tests/Avalonia.DesignerSupport.Tests/RemoteProtocolTests.cs
@@ -9,6 +9,7 @@ using System.Reflection;
 using System.Threading;
 using System.Threading.Tasks;
 using Avalonia.Remote.Protocol;
+using Avalonia.Remote.Protocol.Designer;
 using Avalonia.Remote.Protocol.Viewport;
 using Xunit;
 
@@ -109,6 +110,16 @@ namespace Avalonia.DesignerSupport.Tests
                     return Guid.NewGuid().ToString();
                 if (t == typeof(Guid))
                     return Guid.NewGuid();
+                if (t == typeof(Exception))
+                    return new Exception("Here");
+                if (t == typeof(ExceptionDetails))
+                    return new ExceptionDetails
+                    {
+                        ExceptionType = "Exception",
+                        LineNumber = 5,
+                        LinePosition = 6,
+                        Message = "Here",
+                    };
                 throw new Exception($"Doesn't know how to fabricate a random value for {t}, path {pathInfo}");
             }
             
diff --git a/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/EventTests.cs b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/EventTests.cs
new file mode 100644
index 0000000000..6ea3015138
--- /dev/null
+++ b/tests/Avalonia.Markup.Xaml.UnitTests/Xaml/EventTests.cs
@@ -0,0 +1,66 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
+using Avalonia.Controls;
+using Avalonia.Input;
+using Portable.Xaml;
+using Xunit;
+
+namespace Avalonia.Markup.Xaml.UnitTests.Xaml
+{
+    public class EventTests
+    {
+        [Fact]
+        public void Event_Is_Attached()
+        {
+            var xaml = @"<Button xmlns='https://github.com/avaloniaui' Click='OnClick'/>";
+            var loader = new AvaloniaXamlLoader();
+            var target = new MyButton();
+
+            loader.Load(xaml, rootInstance: target);
+            RaiseClick(target);
+
+            Assert.True(target.Clicked);
+        }
+
+        [Fact]
+        public void Exception_Is_Thrown_If_Event_Not_Found()
+        {
+            var xaml = @"<Button xmlns='https://github.com/avaloniaui' Click='NotFound'/>";
+            var loader = new AvaloniaXamlLoader();
+            var target = new MyButton();
+
+            Assert.Throws<XamlObjectWriterException>(() => loader.Load(xaml, rootInstance: target));
+        }
+
+        [Fact]
+        public void Exception_Is_Not_Thrown_If_Event_Not_Found_In_Design_Mode()
+        {
+            var xaml = @"<Button xmlns='https://github.com/avaloniaui' Click='NotFound'/>";
+            var loader = new AvaloniaXamlLoader { IsDesignMode = true };
+            var target = new MyButton();
+
+            loader.Load(xaml, rootInstance: target);
+        }
+
+        private void RaiseClick(MyButton target)
+        {
+            target.RaiseEvent(new KeyEventArgs
+            {
+                RoutedEvent = Button.KeyDownEvent,
+                Key = Key.Enter,
+            });
+        }
+
+        class MyButton : Button
+        {
+            public bool Clicked { get; private set; }
+
+            public void OnClick(object sender, EventArgs e)
+            {
+                Clicked = true;
+            }
+        }
+    }
+}
diff --git a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/DrawOperationTests.cs b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/DrawOperationTests.cs
index 2060cc7170..6a1f08a384 100644
--- a/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/DrawOperationTests.cs
+++ b/tests/Avalonia.Visuals.UnitTests/Rendering/SceneGraph/DrawOperationTests.cs
@@ -61,6 +61,19 @@ namespace Avalonia.Visuals.UnitTests.Rendering.SceneGraph
             Assert.Equal(1, bitmap.RefCount);
         }
 
+        [Fact]
+        public void HitTest_On_Geometry_Node_With_Zero_Transform_Does_Not_Throw()
+        {
+            var geometry = Mock.Of<IGeometryImpl>();
+            var geometryNode = new GeometryNode(
+                new Matrix(),
+                Brushes.Black,
+                null,
+                geometry);
+
+            geometryNode.HitTest(new Point());
+        }
+
         private class TestDrawOperation : DrawOperation
         {
             public TestDrawOperation(Rect bounds, Matrix transform, Pen pen)