close dropdown on destroy, fixes #17275
(cherry-picked from 697870d0ef70e56724959f69052c2ffff4576efa)
Monitor focus from Menu rather than MenuItem, refs #7111.
This removes the indirect _FocusMixin dependency from MenuItem.
(cherry picked from commit 116331ffca4600b1c4ee6e3f94e7faf83ae2a57b)
InlineEditBox: make _FocusMixin dependency explicit
_TextBoxMixin: make _FocusWidget dependency explicit
get dijit/focus test case working again