Can't put check mark here.

This is a menu design error indicating that you tried to select Checked on a menu item that does not support check marks. The following situations can cause this error:

• You tried to select Checked in the Menu Editor for a top-level menu item.
  
  
• You selected Checked for some menu item which has a submenu such as a cascading sub-menu.
  
  
• You chose some menu such as a MDI Window list menu that cannot be checked.