UINT ArrangeIconicWindows();
Arranges all the minimized (iconic) child windows.
This member function also arranges icons on the desktop window, which covers the entire screen. The GetDesktopWindow member function retrieves a pointer to the desktop window object.
To arrange iconic MDI child windows in an MDI client window, call CMDIFrameWnd::MDIIconArrange.
The height of one row of icons, or 0 if there were no icons.
CWnd::GetDesktopWindow, CMDIFrameWnd::MDIIconArrange, ::ArrangeIconicWindows