Solution for gesture failure

[LannyC]

In iOS 8, occasionally the four-finger swipe gestures for switching and closing apps stop working. I've found that I can get them going again by simply swiping up the Control Center then putting it away. No need to toggle the switch in Settings. Hope this helps everyone.

 

[J. A.]

Useful.
Also works with pulling down Notification Center and sliding up again, or force closing an app.