C1CommandMdiList component is a command which, at run time, expands to a list of items corresponding to the MDI child windows of the current window. Note that this is not a submenu. You can either put this command in a submenu all by itself, or add other menu items before or after it.
The following image shows how the C1CommandMdiList displays a list of items corresponding to the MDI child windows.
You can restrict the amount of items the C1CommandMdiList command displays in its Menu's list by setting the MaxItems to the desired amount of items you would like to show. The default value for this property is 10.
You can also show hidden MDI windows in the menu's list by setting ListHidden to True.
For more information on how to accomplish creating a Window list for MDI child windows, see Creating a Window List for an MDI Form.