So we just started using the Composite Application Block for a Silverlight project. Greate stuff. But we quickly ran into an issue where we were unable to make a subview stretch to fill out its containing region. Turned out that a template containing a DockPanel needed to be added to the ItemsControl representing the region.
After lots of playing arround, I finally found the solution here:
http://www.global-webnet.net/blogengine/post/2008/08/09/CompositeWPF-Getting-your-view-to-stretch-vertically-as-well-as-horizontally.aspx
Tags: CAB, Composite Application Block, ItemsControl, Microsoft, Silverlight, Vertical stretch, View, WPF