Update the mouse cursor in a couple more cases
Reset cursor if kAcceptKeyboardFocusFlag is set.

This basically affects menus which are not movable, and not
resizable but have that flag set because they take input anyway.
This change shows the regular cursor over menu windows even
in window management mode when ctrl+alt are held down.

Also rename _SetNowAllowedCursor to _SetNotAllowedCursor, typo.