Behaviors: Introducing the concept of Behavior with Blend in WPF which benefit from full designer support, and thus providing a much higher level of accessibility to developers and designers. Behaviors allow designers to create production-quality interactivity without writing
code. They work in WPF and Silverlight. Designers can use behaviors right on the Blend art board – they can be applied to elements with drag and drop, and many have configuration options available through the property inspector. They are not just a prototyping tool that is impossible to use in a production scenario.