diff --git a/Sources/WpfApp/MainWindow.xaml.cs b/Sources/WpfApp/MainWindow.xaml.cs
index 4778f80..a3c290f 100644
--- a/Sources/WpfApp/MainWindow.xaml.cs
+++ b/Sources/WpfApp/MainWindow.xaml.cs
@@ -380,7 +380,7 @@ namespace WpfApp
                 {
                     Width = CircleStartSize,
                     Height = CircleStartSize,
-                    Fill = Brushes.Red,
+                    Fill = Brushes.Purple,
                     Opacity = 0.5
                 };