Shake to undo typing was a feature (gesture?) that I discovered purely by accident and that too after owning an iOS device for a whole year. I’ve never intentionally used it though it has popped on my screen unwanted by accident. Of all the gestures that iOS supports, not only is the shake to undo one the least I’ve ever used, it’s also the silliest to execute. As of iOS 9 you can finally disable it from the Settings app. Here’s how.
Open the Settings app and go to General>Accessibility>Shake to Undo. Simply tap the switch on the Shake to Undo screen to turn the gesture off.
The Shake to Undo feature, or rather the shake gesture is popularly used in alarm clock apps with the objective being that if you have to get up and vigorously shake your phone to turn the alarm off, you will be less inclined to go back to sleep afterwards. Turning the feature off only disables the Shake to undo gesture for ‘Undo typing’ though so if you have an app that relies on this gesture to function, rest assured that it will continue to work.
The Shake to Undo gesture isn’t easy to bring up by accident but it does happen. As the hardware in iPhones improves, the gyroscopes in the device becomes more and more precise in detecting movement which, while awesome on the whole, can result in the ‘Undo Typing’ message to pop up if you’re on a bus ride that’s too bumpy.