diff --git a/examples/window/window/app.py b/examples/window/window/app.py
index eecf6c6044..9ef3e350a2 100644
--- a/examples/window/window/app.py
+++ b/examples/window/window/app.py
@@ -170,11 +170,15 @@ def startup(self):
         screen_change_btns_box = toga.Box(
             children=[toga.Label(text="Move current window to:")]
         )
+
+        def do_screen_change(screen):
+            self.current_window.screen = screen
+
         for screen in self.screens:
             screen_change_btns_box.add(
                 toga.Button(
                     text=screen.name,
-                    on_press=lambda x: setattr(self.current_window, "screen", screen),
+                    on_press=lambda x, screen=screen: do_screen_change(screen),
                 )
             )
         self.main_box = toga.Box(