■ More than one condition can cause this error:
 
  • The Checked property for a menu control can't be selected
    when that control is a top-level menu title.
 
  • The Separator property for a menu control can't be set
    when the control is a top-level menu title.
 
  • The Visible property can't be set to False(0) for the
    last visible submenu on a parent menu. You can't have a
    parent menu with no visible submenu items.
 
■ Possible solution:
 
  • Change your reference to the Checked, Separator, or
    Visible property to conform to the usage rules outlined
    above.
 
■ If you need additional help, move the cursor to a keyword
  and press F1 to open the Help window.