Welcome to TNW Basics , a collection of tips, guides, and advice on how to easily get the most out of your gadgets, apps, and other stuff.

Have you ever been messing around with your iPhone and the whole display randomly slides halfway down your screen for no apparent reason? And how you can get it to not do that? Never fear, we’re here for you.

This is actually a feature called Reachability. By moving the top of the screen down, it allows users who might not be able to reach the far corners of their screen — say, because of small hands or because of a disability — to reach it with ease. And it definitely makes it easier to use certain gestures that require you to brush the top of your phone, such as accessing notifications, because the swiping point for those now becomes the middle of the screen. But if you can reach all your phone‘s real estate just fine, it’s a useless annoyance (especially when accidentally triggered).

Here’s how you’re doing, and how you can fix it.

There are two different ways to trigger Reachability, depending on what iPhone model you have. On older models, you do it by tapping — not pressing — the Home button twice. For iPhones X or newer, you swipe down on the bottom edge of the screen. To get it to move back up, just swipe up on the translucent arrow.

To turn this off, go to the Accessibility settings. From there, find the Touch options, and you’ll see the Reachability toggle.

Turn this off, and you won’t accidentally make your phone screen slide down again. Good luck!