Using the MdiListTool creates many different ways to display the child window list in an MDI application.  A MdiListTool is a tool array tool with a list of items that displays all open Mdi children of the application.  This tool can be used in a menu, toolbar, and a stausbar.  It can also have different styles including Inline, PopupToolbar, and PopupMenu.  From these different styles you can customize the look from there with options to display the item number, the maximum number of items you want displayed, and if you want, the items grouped all by setting simple properties.

Attached is a sample showing some of the above functionality.  You can also find a walkthrough in our help file:
ms-help://dd.SharpUI.1033/ddSharpUI/suiwlkMultipleDocumentInterface.html