MdiList Property is not on the list of menuitem properties when working with mdi container window

Thanks for the response; but another also includes to put the code in form_load() (I assumed in the midi container code)

// Create a MenuStrip control with a new window.
MenuStrip ms = new MenuStrip();
ToolStripMenuItem windowMenu = new ToolStripMenuItem("Window");
ToolStripMenuItem windowNewMenu = new ToolStripMenuItem("New", null, new EventHandler(windowNewMenu_Click));
windowMenu.DropDownItems.Add(windowNewMenu);
((ToolStripDropDownMenu)(windowMenu.DropDown)).ShowImageMargin = false;
((ToolStripDropDownMenu)(windowMenu.DropDown)).ShowCheckMargin = true;

// Assign the ToolStripMenuItem that displays 
// the list of child forms.
ms.MdiWindowListItem = windowMenu;

// Add the window ToolStripMenuItem to the MenuStrip.
ms.Items.Add(windowMenu);

// Dock the MenuStrip to the top of the form.
ms.Dock = DockStyle.Top;

// The Form.MainMenuStrip property determines the merge target.
this.MainMenuStrip = ms;