Some Don Box Holiday Humor and Avalon child layout
In case someone hasn't seen this, here is some holiday satire from Don Box and Chris Anderson.
The associated MSDN TV video shows how to do your own layout panel. Interestingly, Chris introduces the two pass Measure/Arrange layout model in Avalon as a new concept that allows “content negotiation, sized-content ...” Later, he explains that page layout may call Measure multiple times before calling Arrange to discover the optimal layout.
Shows Panel, Measure, MeasureOverride, Arrange, ArrangeOverride, DesiredSize (Can't seem to find proper documentation for ...Override in the beta documentation)