Hah! A fix of my own to Tim's code!

Unix bindings for <<toggle-tabs>> and <<change-indentwidth>> were
missing, and somehow that meant the events were never generated,
even though they were in the menu.  The new Unix bindings are now
the same as the Windows bindings (M-t and M-u).

Tools/idle/AutoIndent.py

@@ -84,6 +84,8 @@ class AutoIndent:
         '<<uncomment-region>>': ['<Alt-Key-4>', '<Meta-Key-4>'],
         '<<tabify-region>>': ['<Alt-Key-5>', '<Meta-Key-5>'],
         '<<untabify-region>>': ['<Alt-Key-6>', '<Meta-Key-6>'],
+        '<<toggle-tabs>>': ['<Alt-Key-t>'],
+        '<<change-indentwidth>>': ['<Alt-Key-u>'],
     }
 
     # usetabs true  -> literal tab characters are used by indent and