diff -r df8857c6f3eb Lib/tkinter/__init__.py
--- a/Lib/tkinter/__init__.py	Sun Jul 17 11:35:35 2016 +0300
+++ b/Lib/tkinter/__init__.py	Sun Jul 24 08:29:48 2016 +0300
@@ -1340,7 +1340,24 @@ class Misc:
         for n in name:
             if not n:
                 break
-            w = w.children[n]
+            try:
+                w = w.children[n]
+            except KeyError:
+                if '#' not in n:
+                    raise
+                # This is a cloned menu.  The name of cloned menu is generated
+                # from the full path of the original widget by replacing
+                # '.'s with '#'s and optionally appending an integer.
+                n = n.split("#")[-1]
+                while True:
+                    try:
+                        w = w.children[n]
+                    except KeyError:
+                        if not n or n[-1] not in '0123456789':
+                            raise
+                        n = n[:-1]
+                    else:
+                        break
 
         return w
     _nametowidget = nametowidget