When you close a Metro application in Windows 8, its more like it gets paused, rather than completely closes. This allows us to quickly switch between applications (think “resume”) without having to launch the application from scratch. Here’s how we can delete our Metro application history as well as exit any applications running in the background.

Deleting Your Application History

Press the Windows + I key combination, when the sidebar appears go ahead and click on the “More PC Settings” section.

When the new “Metro Control Panel” loads you’re going to want to head over to the General Section.

On the right-hand side, a simple click of the Delete button in the App switching section will do the trick.

If you take a closer look at Task manager you will also notice that it closes any 3rd Party Metro applications that were running in the background.

Of course, it also removes them from the application switching list, as promised.

Source: howtogeek