Windows 8 introduced the Metro interface which was later rebranded as the Modern UI. This tile-based interface breaks away from the desktop and allows apps to be run at full screen with no other distractions. Windows 8.1 introduces a new way to restart such apps.
Traditional windows furniture such as the titlebar, minimize, maximize and close buttons are absent from Modern apps. To close them you need to drag them from the top of the screen to the bottom. The app will first shrink to about a quarter of its usual size before reducing to a miniature icon when you reach the bottom of the screen.
If you’re using a regular mouse, this is a simple matter of grabbing the top of the window by clicking with the left mouse button, keeping the button held, dragging off the bottom of the screen and releasing the button.
The process is virtually the same for touch screen devices — you just need to swipe down from the very top edge of screen. Keep dragging after the app window reaches its smallest size and it will then vanish and close.
This method still works in Windows 8.1, but there is also a very handy new option for restarting apps. Rather than closing and then re-opening an app, there is a new option available to you.
Now when you drag an app window to the bottom of the screen, do not drag it straight off the bottom. Instead, hold the miniature window in place at the bottom of the screen and you’ll notice that it suddenly flips around front to back.
Once this happens, move your mouse back up (or drag your finger back up on a touchscreen device) and you’ll see a larger version of the app’s startup screen. Release the window and the app will restart.