diff --git a/samples/XamlTestApplication/Views/MainWindow.paml b/samples/XamlTestApplication/Views/MainWindow.paml
index 0f37faa54c..0794d15aff 100644
--- a/samples/XamlTestApplication/Views/MainWindow.paml
+++ b/samples/XamlTestApplication/Views/MainWindow.paml
@@ -2,7 +2,6 @@
         xmlns="https://github.com/perspex"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
         Title="Perspex Test Application" Height="350" Width="525" SizeToContent="WidthAndHeight" >
-   
     <Grid RowDefinitions="Auto,*,Auto" ColumnDefinitions="*,*">
         <TabControl Grid.Row="1" Grid.ColumnSpan="2" Padding="5">
             <TabControl.Transition>
@@ -49,7 +48,7 @@
             </TabItem>
             <TabItem Header="Lists">
                 <StackPanel Orientation="Horizontal" VerticalAlignment="Center" HorizontalAlignment="Center">
-                    <ListBox>
+                    <ListBox SelectedIndex="0">
                         <ListBoxItem>
                             <StackPanel>
                                 <TextBlock Text="Item 1" FontSize="24" />
@@ -63,7 +62,7 @@
                             </StackPanel>
                         </ListBoxItem>
                     </ListBox>
-                    <DropDown VerticalAlignment="Center">
+                    <DropDown VerticalAlignment="Center" SelectedIndex="0">
                         <StackPanel>
                             <TextBlock Text="Item 1" FontSize="24" />
                             <TextBlock Text="Item 1 Value" />
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
index e8808ff285..12ef408fcd 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
@@ -22,23 +22,37 @@ using Perspex.Media.Imaging;
 using Perspex.Metadata;
 using Perspex.Platform;
 using Perspex.Styling;
+using Perspex.Controls.Primitives;
 
 namespace Perspex.Markup.Xaml.Context
 {
-    public class PerspexWiringContext : IWiringContext
+    public class PerspexWiringContext : WiringContext
     {
-        private readonly WiringContext _context;
         private const string PerspexNs = "https://github.com/perspex";
 
         public PerspexWiringContext(ITypeFactory typeFactory)
+            : this(typeFactory, new TypeFeatureProvider(GetContentPropertyProvider(), GetConverterProvider()))
         {
-            var featureProvider = new TypeFeatureProvider(GetContentPropertyProvider(), GetConverterProvider());
+        }
 
+        public PerspexWiringContext(ITypeFactory typeFactory, TypeFeatureProvider featureProvider)
+            : base(CreateTypeContext(typeFactory, featureProvider), featureProvider)
+        {
+        }
+
+        private static ITypeContext CreateTypeContext(ITypeFactory typeFactory, TypeFeatureProvider featureProvider)
+        {
             var xamlNamespaceRegistry = CreateXamlNamespaceRegistry();
             var perspexPropertyBinder = new PerspexPropertyBinder(featureProvider.ConverterProvider);
-            var xamlTypeRepository = new PerspexTypeRepository(xamlNamespaceRegistry, typeFactory, featureProvider, perspexPropertyBinder);
-            var typeContext = new TypeContext(xamlTypeRepository, xamlNamespaceRegistry, typeFactory);
-            _context = new WiringContext(typeContext, featureProvider);
+            var typeRepository = new PerspexTypeRepository(xamlNamespaceRegistry, typeFactory, featureProvider, perspexPropertyBinder);
+
+            typeRepository.RegisterMetadata(new Metadata<Setter>().WithMemberDependency(x => x.Value, x => x.Property));
+            typeRepository.RegisterMetadata(
+                new Metadata<SelectingItemsControl>()
+                .WithMemberDependency(x => x.SelectedIndex, x => x.Items)
+                .WithMemberDependency(x => x.SelectedItem, x => x.Items));
+
+            return new TypeContext(typeRepository, xamlNamespaceRegistry, typeFactory);
         }
 
         private static XamlNamespaceRegistry CreateXamlNamespaceRegistry()
@@ -116,9 +130,5 @@ namespace Perspex.Markup.Xaml.Context
 
             return contentPropertyProvider;
         }
-
-        public ITypeContext TypeContext => _context.TypeContext;
-
-        public ITypeFeatureProvider FeatureProvider => _context.FeatureProvider;
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/OmniXAML b/src/Markup/Perspex.Markup.Xaml/OmniXAML
index 1aa1e5080b..49e6ec001f 160000
--- a/src/Markup/Perspex.Markup.Xaml/OmniXAML
+++ b/src/Markup/Perspex.Markup.Xaml/OmniXAML
@@ -1 +1 @@
-Subproject commit 1aa1e5080b04ccf40baef4420ee29ffef9303811
+Subproject commit 49e6ec001f5873cf2290e0bc1f6f06ca9b9cf808
diff --git a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
index 3ed9a50f31..f6b9dcf204 100644
--- a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
+++ b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
@@ -59,6 +59,7 @@
     <Compile Include="DataBinding\ChangeTracking\PropertyPath.cs" />
     <Compile Include="DataBinding\ChangeTracking\TargettedProperty.cs" />
     <Compile Include="Context\PerspexParserFactory.cs" />
+    <Compile Include="OmniXAML\Source\Glass\AutoKeyDictionary.cs" />
     <Compile Include="OmniXAML\Source\Glass\ChangeTracking\ObservableProperty.cs" />
     <Compile Include="OmniXAML\Source\Glass\ChangeTracking\ObservablePropertyChain.cs" />
     <Compile Include="OmniXAML\Source\Glass\ChangeTracking\Property.cs" />
diff --git a/src/Perspex.Controls/DropDown.cs b/src/Perspex.Controls/DropDown.cs
index a465ce68a9..eb78e13cbc 100644
--- a/src/Perspex.Controls/DropDown.cs
+++ b/src/Perspex.Controls/DropDown.cs
@@ -140,6 +140,8 @@ namespace Perspex.Controls
 
             if (control != null)
             {
+                control.Measure(Size.Infinity);
+
                 SelectionBoxItem = new Rectangle
                 {
                     Width = control.DesiredSize.Width,
diff --git a/src/Perspex.Controls/ItemsControl.cs b/src/Perspex.Controls/ItemsControl.cs
index 2939347e67..c1e303147c 100644
--- a/src/Perspex.Controls/ItemsControl.cs
+++ b/src/Perspex.Controls/ItemsControl.cs
@@ -155,6 +155,8 @@ namespace Perspex.Controls
         /// <param name="e">The event args.</param>
         protected virtual void ItemsChanged(PerspexPropertyChangedEventArgs e)
         {
+            System.Diagnostics.Debug.WriteLine($"{this.GetType().Name} set items");
+
             var incc = e.OldValue as INotifyCollectionChanged;
 
             if (incc != null)
diff --git a/src/Perspex.Controls/Primitives/SelectingItemsControl.cs b/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
index 371a3a96a9..811cc7bb3e 100644
--- a/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
+++ b/src/Perspex.Controls/Primitives/SelectingItemsControl.cs
@@ -299,6 +299,8 @@ namespace Perspex.Controls.Primitives
         /// <param name="e">The event args.</param>
         private void SelectedIndexChanged(PerspexPropertyChangedEventArgs e)
         {
+            System.Diagnostics.Debug.WriteLine($"{this.GetType().Name} set selected index");
+
             var index = (int)e.OldValue;
 
             if (index != -1)
diff --git a/src/Perspex.Controls/TextBlock.cs b/src/Perspex.Controls/TextBlock.cs
index 463173cbc9..c9959ebeb3 100644
--- a/src/Perspex.Controls/TextBlock.cs
+++ b/src/Perspex.Controls/TextBlock.cs
@@ -235,9 +235,9 @@ namespace Perspex.Controls
         protected virtual FormattedText CreateFormattedText(Size constraint)
         {
             var result = new FormattedText(
-                Text,
-                FontFamily,
-                FontSize,
+                Text ?? string.Empty,
+                FontFamily ?? "Ariel",
+                FontSize > 0 ? FontSize : 12,
                 FontStyle,
                 TextAlignment,
                 FontWeight);
diff --git a/src/Perspex.SceneGraph/Media/FormattedText.cs b/src/Perspex.SceneGraph/Media/FormattedText.cs
index f5f390c609..245db90eb6 100644
--- a/src/Perspex.SceneGraph/Media/FormattedText.cs
+++ b/src/Perspex.SceneGraph/Media/FormattedText.cs
@@ -29,9 +29,10 @@ namespace Perspex.Media
             TextAlignment textAlignment,
             FontWeight fontWeight)
         {
-            //TODO: Find out why it was null in the first place. Demo project - AvalonStudio
-            //https://github.com/VitalElement/AvalonStudio/commit/787fb9396feb74e6ca6bd4e08436269a349df9c6
-            text = text ?? "";
+            Contract.Requires<ArgumentNullException>(text != null);
+            Contract.Requires<ArgumentNullException>(fontFamilyName != null);
+            Contract.Requires<ArgumentException>(fontSize > 0);
+
             Text = text;
             FontFamilyName = fontFamilyName;
             FontSize = fontSize;