Backport of r68153
diff --git a/Lib/idlelib/help.txt b/Lib/idlelib/help.txt
index 76cccf0..7bfd2ca 100644
--- a/Lib/idlelib/help.txt
+++ b/Lib/idlelib/help.txt
@@ -90,7 +90,10 @@
 	Configure IDLE -- Open a configuration dialog.  Fonts, indentation,
                           keybindings, and color themes may be altered.
                           Startup Preferences may be set, and Additional Help
-                          Souces can be specified.
+                          Sources can be specified.
+			  
+			  On MacOS X this menu is not present, use
+			  menu 'IDLE -> Preferences...' instead.
 	---
 	Code Context --	  Open a pane at the top of the edit window which
 			  shows the block context of the section of code