App switching allows you to switch between apps when you move your mouse over to the top left corner of the screen. If you want to enable or disable this option in Windows 8, here is how you can do it:
1. Hover your mouse to the top right corner of the screen to let the Charms bar appear. Now click on Settings.
2. Click Change PC Settings in the bottom right corner of the screen
3. Select General in the left pane and move the slider under App switching to on or off to enable to disable App switching.