diff --git a/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml b/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml
new file mode 100644
index 000000000..9f9e39f3d
--- /dev/null
+++ b/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml
@@ -0,0 +1,9 @@
+<Window x:Class="ILSpy.BamlDecompiler.Tests.Cases.ReadonlyProperty" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:ILSpy.BamlDecompiler.Tests.Cases" Title="ReadonlyProperty" Height="450" Width="800">
+	<Grid>
+		<local:MyControl>
+			<local:MyControl.DataTypes>
+				<x:TypeExtension TypeName="Brush" />
+			</local:MyControl.DataTypes>
+		</local:MyControl>
+    </Grid>
+</Window>
diff --git a/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml.cs b/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml.cs
new file mode 100644
index 000000000..6e4d81f8e
--- /dev/null
+++ b/ILSpy.BamlDecompiler.Tests/Cases/ReadonlyProperty.xaml.cs
@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Data;
+using System.Windows.Documents;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Shapes;
+
+namespace ILSpy.BamlDecompiler.Tests.Cases
+{
+	/// <summary>
+	/// Interaction logic for ReadonlyProperty.xaml
+	/// </summary>
+	public partial class ReadonlyProperty : Window
+	{
+		public ReadonlyProperty()
+		{
+			InitializeComponent();
+		}
+	}
+}