Multiple Window support is one of the important feature in Silverlight 5. Using this you can have additional top level Window on top of your trusted Silverlight Out-of-Browser application. Yes, you read correct. It only works in Out-of-Browser Silverlight application and hence you cannot open it inside a browser.
So, what is this new Window and how to use it in our application? Let's have some discussion on it. After it you will be able to know about it more.