diff -r 7b456ce3c36e examples/mainwindows/mdi/mdi.py
--- a/examples/mainwindows/mdi/mdi.py	Fri May 28 13:55:02 2010 +0100
+++ b/examples/mainwindows/mdi/mdi.py	Fri May 28 15:19:13 2010 +0100
@@ -258,7 +258,7 @@
             action.setCheckable(True)
             action.setChecked(child == self.activeMdiChild())
             action.triggered.connect(self.windowMapper.map)
-            self.windowMapper.setMapping(action, child)
+            self.windowMapper.setMapping(action, window)
 
     def createMdiChild(self):
         child = MdiChild()