diff --git a/samples/XamlTestApplication/Views/MainWindow.xaml b/samples/XamlTestApplication/Views/MainWindow.xaml
index 3294edb8b0..da27d04242 100644
--- a/samples/XamlTestApplication/Views/MainWindow.xaml
+++ b/samples/XamlTestApplication/Views/MainWindow.xaml
@@ -2,11 +2,7 @@
         xmlns="https://github.com/grokys/Perspex"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
         Title="Perspex Test Application" Height="350" Width="525">
-    <Grid>
-        <Grid.RowDefinitions>
-            <RowDefinition Height="Auto" />
-            <RowDefinition />
-        </Grid.RowDefinitions>
+    <Grid RowDefinitions="Auto,*">
         <TabControl Grid.Row="1">
             <TabItem Header="Buttons">
                 <StackPanel HorizontalAlignment="Center" Width="200" VerticalAlignment="Center">
diff --git a/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs b/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
index f78418f20d..88a67c8287 100644
--- a/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Context/PerspexWiringContext.cs
@@ -83,10 +83,12 @@ namespace Perspex.Markup.Xaml.Context
             var typeConverterProvider = new TypeConverterProvider();
             var converters = new[]
             {
-                new TypeConverterRegistration(typeof (Bitmap), new BitmapConverter()),
-                new TypeConverterRegistration(typeof (GridLength), new GridLengthTypeConverter()),
-                new TypeConverterRegistration(typeof (Brush), new BrushConverter()),
-                new TypeConverterRegistration(typeof (Thickness), new ThicknessConverter()),
+                new TypeConverterRegistration(typeof(Bitmap), new BitmapConverter()),
+                new TypeConverterRegistration(typeof(Brush), new BrushConverter()),
+                new TypeConverterRegistration(typeof(ColumnDefinitions), new ColumnDefinitionsTypeConverter()),
+                new TypeConverterRegistration(typeof(GridLength), new GridLengthTypeConverter()),
+                new TypeConverterRegistration(typeof(RowDefinitions), new RowDefinitionsTypeConverter()),
+                new TypeConverterRegistration(typeof(Thickness), new ThicknessConverter()),
             };
 
             typeConverterProvider.AddAll(converters);
@@ -98,13 +100,13 @@ namespace Perspex.Markup.Xaml.Context
             var contentPropertyProvider = new ContentPropertyProvider();
             var contentProperties = new Collection<ContentPropertyDefinition>
             {
-                new ContentPropertyDefinition(typeof (ContentControl), "Content"),
-                new ContentPropertyDefinition(typeof (Decorator), "Child"),
-                new ContentPropertyDefinition(typeof (ItemsControl), "Items"),
-                new ContentPropertyDefinition(typeof (Panel), "Children"),
-                new ContentPropertyDefinition(typeof (TextBlock), "Text"),
-                new ContentPropertyDefinition(typeof (TextBox), "Text"),
-                new ContentPropertyDefinition(typeof (XamlDataTemplate), "Content"),
+                new ContentPropertyDefinition(typeof(ContentControl), "Content"),
+                new ContentPropertyDefinition(typeof(Decorator), "Child"),
+                new ContentPropertyDefinition(typeof(ItemsControl), "Items"),
+                new ContentPropertyDefinition(typeof(Panel), "Children"),
+                new ContentPropertyDefinition(typeof(TextBlock), "Text"),
+                new ContentPropertyDefinition(typeof(TextBox), "Text"),
+                new ContentPropertyDefinition(typeof(XamlDataTemplate), "Content"),
             };
 
             contentPropertyProvider.AddAll(contentProperties);
diff --git a/src/Markup/Perspex.Markup.Xaml/Converters/ColumnDefinitionsTypeConverter.cs b/src/Markup/Perspex.Markup.Xaml/Converters/ColumnDefinitionsTypeConverter.cs
new file mode 100644
index 0000000000..14893cd1db
--- /dev/null
+++ b/src/Markup/Perspex.Markup.Xaml/Converters/ColumnDefinitionsTypeConverter.cs
@@ -0,0 +1,36 @@
+// -----------------------------------------------------------------------
+// <copyright file="ColumnDefinitionsTypeConverter.cs" company="Steven Kirk">
+// Copyright 2015 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Markup.Xaml.Converters
+{
+    using System;
+    using System.Globalization;
+    using Controls;
+    using OmniXaml.TypeConversion;
+
+    public class ColumnDefinitionsTypeConverter : ITypeConverter
+    {
+        public bool CanConvertFrom(IXamlTypeConverterContext context, Type sourceType)
+        {
+            return sourceType == typeof(string);
+        }
+
+        public bool CanConvertTo(IXamlTypeConverterContext context, Type destinationType)
+        {
+            return false;
+        }
+
+        public object ConvertFrom(IXamlTypeConverterContext context, CultureInfo culture, object value)
+        {
+            return new ColumnDefinitions((string)value);
+        }
+
+        public object ConvertTo(IXamlTypeConverterContext context, CultureInfo culture, object value, Type destinationType)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/Converters/GridLengthTypeConverter.cs b/src/Markup/Perspex.Markup.Xaml/Converters/GridLengthTypeConverter.cs
index 5609597369..1eea9e90d0 100644
--- a/src/Markup/Perspex.Markup.Xaml/Converters/GridLengthTypeConverter.cs
+++ b/src/Markup/Perspex.Markup.Xaml/Converters/GridLengthTypeConverter.cs
@@ -13,39 +13,24 @@ namespace Perspex.Markup.Xaml.Converters
 
     public class GridLengthTypeConverter : ITypeConverter
     {
-        public object ConvertFrom(IXamlTypeConverterContext context, CultureInfo culture, object value)
+        public bool CanConvertFrom(IXamlTypeConverterContext context, Type sourceType)
         {
-            var str = value as string;
-
-            if (str != null)
-            {
-                if (string.Equals(str, "Auto"))
-                {
-                    return new GridLength(0, GridUnitType.Auto);
-                }
-            }
-
-            return new GridLength(1, GridUnitType.Star);
+            return sourceType == typeof(string);
         }
 
-        public object ConvertTo(IXamlTypeConverterContext context, CultureInfo culture, object value, Type destinationType)
+        public bool CanConvertTo(IXamlTypeConverterContext context, Type destinationType)
         {
-            if ((string) value == "Auto")
-            {
-                return new GridLength(0, GridUnitType.Auto);
-            }
-
-            return new GridLength(1, GridUnitType.Star);
+            return false;
         }
 
-        public bool CanConvertTo(IXamlTypeConverterContext context, Type destinationType)
+        public object ConvertFrom(IXamlTypeConverterContext context, CultureInfo culture, object value)
         {
-            return true;
+            return GridLength.Parse((string)value);
         }
 
-        public bool CanConvertFrom(IXamlTypeConverterContext context, Type sourceType)
+        public object ConvertTo(IXamlTypeConverterContext context, CultureInfo culture, object value, Type destinationType)
         {
-            return true;
+            throw new NotImplementedException();
         }
     }
 }
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/Converters/RowDefinitionsTypeConverter.cs b/src/Markup/Perspex.Markup.Xaml/Converters/RowDefinitionsTypeConverter.cs
new file mode 100644
index 0000000000..a432584224
--- /dev/null
+++ b/src/Markup/Perspex.Markup.Xaml/Converters/RowDefinitionsTypeConverter.cs
@@ -0,0 +1,36 @@
+// -----------------------------------------------------------------------
+// <copyright file="RowDefinitionsTypeConverter.cs" company="Steven Kirk">
+// Copyright 2015 MIT Licence. See licence.md for more information.
+// </copyright>
+// -----------------------------------------------------------------------
+
+namespace Perspex.Markup.Xaml.Converters
+{
+    using System;
+    using System.Globalization;
+    using Controls;
+    using OmniXaml.TypeConversion;
+
+    public class RowDefinitionsTypeConverter : ITypeConverter
+    {
+        public bool CanConvertFrom(IXamlTypeConverterContext context, Type sourceType)
+        {
+            return sourceType == typeof(string);
+        }
+
+        public bool CanConvertTo(IXamlTypeConverterContext context, Type destinationType)
+        {
+            return false;
+        }
+
+        public object ConvertFrom(IXamlTypeConverterContext context, CultureInfo culture, object value)
+        {
+            return new RowDefinitions((string)value);
+        }
+
+        public object ConvertTo(IXamlTypeConverterContext context, CultureInfo culture, object value, Type destinationType)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
index 814427175f..f0965e351f 100644
--- a/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
+++ b/src/Markup/Perspex.Markup.Xaml/Perspex.Markup.Xaml.csproj
@@ -38,6 +38,8 @@
     <Compile Include="..\..\Shared\SharedAssemblyInfo.cs">
       <Link>Properties\SharedAssemblyInfo.cs</Link>
     </Compile>
+    <Compile Include="Converters\RowDefinitionsTypeConverter.cs" />
+    <Compile Include="Converters\ColumnDefinitionsTypeConverter.cs" />
     <Compile Include="Converters\ThicknessConverter.cs" />
     <Compile Include="Context\PerspexWiringContext.cs" />
     <Compile Include="GlobalSuppressions.cs" />