diff --git a/src/System.Waf/Samples/BookLibrary/BookLibrary.Library.Presentation/App.xaml b/src/System.Waf/Samples/BookLibrary/BookLibrary.Library.Presentation/App.xaml
index ac6eacfc..3f255fe2 100644
--- a/src/System.Waf/Samples/BookLibrary/BookLibrary.Library.Presentation/App.xaml
+++ b/src/System.Waf/Samples/BookLibrary/BookLibrary.Library.Presentation/App.xaml
@@ -1,6 +1,7 @@
 <Application x:Name="App" x:Class="Waf.BookLibrary.Library.Presentation.App"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    ThemeMode="Light">
     
     <Application.Resources>
         <ResourceDictionary>
diff --git a/src/System.Waf/Samples/InformationManager/Assembler/App.xaml b/src/System.Waf/Samples/InformationManager/Assembler/App.xaml
index 45ed4ad6..04de91c6 100644
--- a/src/System.Waf/Samples/InformationManager/Assembler/App.xaml
+++ b/src/System.Waf/Samples/InformationManager/Assembler/App.xaml
@@ -1,6 +1,7 @@
 <Application x:Class="Waf.InformationManager.Assembler.App"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             ThemeMode="Light">
     <Application.Resources>
         <ResourceDictionary>
             <ResourceDictionary.MergedDictionaries>
diff --git a/src/System.Waf/Samples/Writer/Writer.Presentation/App.xaml b/src/System.Waf/Samples/Writer/Writer.Presentation/App.xaml
index 02818cf4..9d782add 100644
--- a/src/System.Waf/Samples/Writer/Writer.Presentation/App.xaml
+++ b/src/System.Waf/Samples/Writer/Writer.Presentation/App.xaml
@@ -1,6 +1,7 @@
 <Application x:Name="App" x:Class="Waf.Writer.Presentation.App"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    ThemeMode="Light">
     
     <Application.Resources>
         <ResourceDictionary>