diff --git a/sandbox/AvaloniaApplication1/Program.cs b/sandbox/AvaloniaApplication1/Program.cs
index 46bcce9a..1b7bfcc2 100644
--- a/sandbox/AvaloniaApplication1/Program.cs
+++ b/sandbox/AvaloniaApplication1/Program.cs
@@ -19,5 +19,5 @@ public static AppBuilder BuildAvaloniaApp()
             .UsePlatformDetect()
             .WithInterFont()
             .LogToTrace()
-            .UseR3(ex => Logger.Sink?.Log(LogEventLevel.Error, "R3", null, "R3 Unhandled Exception {0}", ex)); // add this line
+            .UseR3(); // add this line
 }
diff --git a/src/R3.Avalonia/AppBuilderR3InitializeExtensions.cs b/src/R3.Avalonia/AppBuilderR3InitializeExtensions.cs
index bc6f1804..18e45899 100644
--- a/src/R3.Avalonia/AppBuilderR3InitializeExtensions.cs
+++ b/src/R3.Avalonia/AppBuilderR3InitializeExtensions.cs
@@ -5,24 +5,29 @@ namespace Avalonia; // Avalonia namespace
 
 public static class AppBuilderR3InitializeExtensions
 {
-    public static AppBuilder UseR3(this AppBuilder builder, Action<Exception> unhandledExceptionHandler)
+    public static AppBuilder UseR3(this AppBuilder builder)
     {
         // need to delay setup, initialize provider(dispatcher) need to determine platform
+        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem());
+    }
+
+    public static AppBuilder UseR3(this AppBuilder builder, Action<Exception> unhandledExceptionHandler)
+    {
         return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler));
     }
 
     public static AppBuilder UseR3(this AppBuilder builder, DispatcherPriority priority, Action<Exception> unhandledExceptionHandler)
     {
-        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler,priority));
+        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler, priority));
     }
 
     public static AppBuilder UseR3(this AppBuilder builder, int framesPerSecond, Action<Exception> unhandledExceptionHandler)
     {
-        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler,framesPerSecond));
+        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler, framesPerSecond));
     }
 
     public static AppBuilder UseR3(this AppBuilder builder, DispatcherPriority priority, int framesPerSecond, Action<Exception> unhandledExceptionHandler)
     {
-        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler,priority, framesPerSecond));
+        return builder.AfterSetup(_ => AvaloniaProviderInitializer.SetDefaultObservableSystem(unhandledExceptionHandler, priority, framesPerSecond));
     }
 }
diff --git a/src/R3.Avalonia/AvaloniaProviderInitializer.cs b/src/R3.Avalonia/AvaloniaProviderInitializer.cs
index 92470e4f..af27cac3 100644
--- a/src/R3.Avalonia/AvaloniaProviderInitializer.cs
+++ b/src/R3.Avalonia/AvaloniaProviderInitializer.cs
@@ -1,9 +1,15 @@
-using Avalonia.Threading;
+using Avalonia.Logging;
+using Avalonia.Threading;
 
 namespace R3.Avalonia;
 
 public static class AvaloniaProviderInitializer
 {
+    public static void SetDefaultObservableSystem()
+    {
+        SetDefaultObservableSystem(ex => Logger.Sink?.Log(LogEventLevel.Error, "R3", null, "R3 Unhandled Exception {0}", ex));
+    }
+
     public static void SetDefaultObservableSystem(Action<Exception> unhandledExceptionHandler)
     {
         ObservableSystem.RegisterUnhandledExceptionHandler(unhandledExceptionHandler);