How to add a BarItem that allows switching between all opened MDI documents

The example illustrates how to add a BarItem with a collection of sub items, which will allow switching between all opened MDI documents in the DocumentGroup. This behavior can be achieved by binding BarLinkContainerItem.ItemLinksSource to the DocumentGroup.Items collection. Place the DataTemplate with the BarCheckItem control to the BarLinkContainerItem.ItemTemplate property. Bind the BarCheckItem.Content property to the DocumentPanel.Caption property to display DocumentPanel's header value in the BarItem's content. Set the BarCheckItem.IsChecked property to DocumentPanel.IsActive by using the Binding to allow switching between all DocumentPanels.