diff --git a/Lib/idlelib/macosx.py b/Lib/idlelib/macosx.py
index b16e0523c01..98d7887b5c0 100644
--- a/Lib/idlelib/macosx.py
+++ b/Lib/idlelib/macosx.py
@@ -238,4 +238,4 @@ def setupApp(root, flist):
         hideTkConsole(root)
         overrideRootMenu(root, flist)
         addOpenEventSupport(root, flist)
-        fixb2context()
+        fixb2context(root)