diff --git a/Lib/idlelib/FileList.py b/Lib/idlelib/FileList.py
index 475cd3d..8318ff1 100644
--- a/Lib/idlelib/FileList.py
+++ b/Lib/idlelib/FileList.py
@@ -43,7 +43,7 @@
     def new(self, filename=None):
         return self.EditorWindow(self, filename)
 
-    def close_all_callback(self, event):
+    def close_all_callback(self, *args, **kwds):
         for edit in self.inversedict.keys():
             reply = edit.close()
             if reply == "cancel":
diff --git a/Lib/idlelib/macosxSupport.py b/Lib/idlelib/macosxSupport.py
index 7d3d57b..909856e 100644
--- a/Lib/idlelib/macosxSupport.py
+++ b/Lib/idlelib/macosxSupport.py
@@ -97,6 +97,11 @@
     if flist:
         root.bind('<<close-all-windows>>', flist.close_all_callback)
 
+        # The binding above doesn't reliably work on all versions of Tk
+        # on MacOSX. Adding command definition below does seem to do the
+        # right thing for now.
+        root.createcommand('exit', flist.close_all_callback)
+
 
     ###check if Tk version >= 8.4.14; if so, use hard-coded showprefs binding
     tkversion = root.tk.eval('info patchlevel')