Building MDI Application in WPF
WPF MDI open source project is a library to add the traditional Windows Forms Multiple Document Interface (MDI) features to WPF. The aim is to resemble the original as much as possible.
WPF MDI includes two themes, Luna (XP) and Aero (Vista & 7) as well as support for custom themes. Themes are used depending on the operating system, although a theme can be set at compile and/or run time also.