Added an About page addition to the test plugin.

TestPlugin/AboutPageAddition.cs

@@ -0,0 +1,35 @@
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
+// This code is distributed under MIT X11 license (for details please see \doc\license.txt)
+
+using System.ComponentModel.Composition;
+using System.Windows;
+using System.Windows.Media;
+
+using ICSharpCode.AvalonEdit.Highlighting;
+using ICSharpCode.ILSpy;
+
+namespace TestPlugin
+{
+	[Export(typeof(IAboutPageAddition))]
+	public class AboutPageAddition : IAboutPageAddition
+	{
+		public void Write(ISmartTextOutput textOutput)
+		{
+			textOutput.WriteLine();
+			textOutput.Write("This is a test.");
+			textOutput.WriteLine();
+			textOutput.WriteLine();
+			textOutput.BeginSpan(new HighlightingColor {
+				Background = new SimpleHighlightingBrush(Colors.Black),
+				FontStyle = FontStyles.Italic,
+				Foreground = new SimpleHighlightingBrush(Colors.Aquamarine)
+			});
+			textOutput.Write("DO NOT PRESS THIS BUTTON --> ");
+			textOutput.AddButton(null, "Test!", (sender, args) => MessageBox.Show("Naughty Naughty!", "Naughty!", MessageBoxButton.OK, MessageBoxImage.Exclamation));
+			textOutput.Write(" <--");
+			textOutput.WriteLine();
+			textOutput.EndSpan();
+			textOutput.WriteLine();
+		}
+	}
+}

TestPlugin/TestPlugin.csproj

@@ -41,6 +41,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <Compile Include="AboutPageAddition.cs" />
     <Compile Include="ContextMenuCommand.cs" />
     <Compile Include="CustomLanguage.cs" />
     <Compile Include="CustomOptionPage.xaml.cs">