bugfix metadata in simple sample

Author: jogibear9988

SimpleSample/MainWindow.xaml.cs

@@ -5,6 +5,7 @@
 using System.Windows.Controls;
 using System.Xml;
 using ICSharpCode.WpfDesign;
+using ICSharpCode.WpfDesign.Designer;
 using ICSharpCode.WpfDesign.Designer.Services;
 using ICSharpCode.WpfDesign.Designer.Xaml;
 using ICSharpCode.WpfDesign.XamlDom;
@@ -28,6 +29,8 @@ public MainWindow()
 		{
 			InitializeComponent();
 
+			BasicMetadata.Register();
+
 			var loadSettings = new XamlLoadSettings();
 			loadSettings.DesignerAssemblies.Add(this.GetType().Assembly);