title: Screen that covers 80% of the screen
body: <p>I am trying to create a windows 8.1 application and wanted to know that is there a control that allows me to create something like popup or messagebox in XAML that covers about 80% of the screen with some margin on either sides of the screen? Like when we click on a button and the screen's brightness gets dim except for the popup that is opened. As an example I have attached an image.<a href="http://i.stack.imgur.com/p7COP.jpg" rel="nofollow">Example from windows settings</a></p>