ui elements in silverlight 3 supports "element-to-element" binding—which allows one element to be bound to the state of another element, as well as a validation mechanism for data binding. unlike silverlight 2, which allowed the applications to save files only to the local isostorage, silverlight 3 applications can save to any location on the file system via the system "save file" dialog. however, the path where the file is saved will still be hidden from the silverlight application. any external assemblies used by silverlight applications are cached too so that they need not be redownloaded for subsequent instantiations of the application.