Stefan Cruysberghs published an article that covers topics like the new Silverlight designer, the Properties window, design-time properties, binding ViewModel properties, showing data in design-time and some other new Silverlight 4 databinding features.
.NET 4.0 and Visual Studio 2010 offer a lot of new features. Also
Silverlight 4 is a major update with many new features (webcam support,
RichText control, HTML content, access to local files, drag and drop,
ICommand, right clicks and mouse wheel support, COM support, clipboard,
unit testing, …). I like all the new features but I was especially
interested in improvements that could help my current developments
which are based on a M-V-VM architecture with ViewModel properties that
are bound to UI controls.