#2503 make singletons compared with "is" not == or !=
Thanks to Wummel for the patch
diff --git a/Lib/idlelib/PyShell.py b/Lib/idlelib/PyShell.py
index f1148e2..f991ae9 100644
--- a/Lib/idlelib/PyShell.py
+++ b/Lib/idlelib/PyShell.py
@@ -932,7 +932,7 @@
                 "The program is still running!\n Do you want to kill it?",
                 default="ok",
                 parent=self.text)
-            if response == False:
+            if response is False:
                 return "cancel"
         if self.reading:
             self.top.quit()