Jevgenij Pankov has created a multi-windows interface for
Silverlight 4 and wanted to share its code with you.
Source: Eugene's Blog
Facing a need to design a web system with rich user interface, we shall make a choice between a page-by-page scenario (so familiar to web developers) and more habitual to end users desktop-like interface. The last one sets up tough claims to developers: functional designers and system analysts shall be able to design complex and usable front-end, architects - to elaborate interaction between all parts of the system, testers - hardly will be happy as well.
On the other part, Silverligh provides great features for building such complex systems. Any attempts to make them with asp/ajax/javascript/jQuery shortly turn into a nightmare. The only one feature richly deserving of more developers' efforts is multi-windows interface. You can easily find commercial packages, providing components for building such interfaces. But if you don't want to pay - take it for free :)