Windows 8 users must be aware that among the several ways to close a Metro app, was by dragging it down towards the edge of the screen and releasing it. Although this closed the app, it remained in memory with near-nil utilization of resources, so that it could be loaded again quickly, should the user chose to load the app again. Of course, Windows 8 did shut down the app at the right time to give way to other apps, if it found the need to release resources.
The behavior changes in Windows 8.1. Now to close Windows Store apps in windows 8.1, when you drag the app to the bottom of the screen, it will be closed, but you will still see it the Task Manager consuming the same amount of resources. It will be in the suspended state.
But you will not see it when you take your mouse to the top-left corner where open apps are shown. If you perform this Close operation & then immediately relaunch the app from Start Screen or Search, the app will terminate & a fresh instance of the app will restart. This is helpful if you want to restart a hung or frozen app.
Close Windows Store apps in Windows 8.1
Microsoft has changed the way to close Metro apps in Windows 8.1. Now you have to drag it towards the bottom and hold it for a few seconds, till it flips to display its icon, says Microsoft. Once this is done you can release it.
The app will now be closed. So in short, to close the app you will have to pause for a couple of seconds before releasing it.
However, you will still see it in the Task Manager for a period of 10 seconds, after which its process will exit from the Task Manager too.
See this post if you want to find out how to change the App closure time in Windows 8.1.