Any time that you're typing on a keyboard in iOS, a little pop-up appears above the key on the keyboard that you tap on. The little preview is nice in some people's opinion, but for others, it gets in the way of the keyboard and they wish it was gone.

Here is an example of the key pop-up while typing:

A new free jailbreak tweak called NoKeyPop by iOS developer PoomSmart is now available completely free of cost in Cydia that does away with the keyboard pop-up while typing. Notably, the tweak does not affect the pop-up that appears when you tap and hold on a key to show its alternate characters.

The tweak adds a simple toggle switch to the Settings application where you can enable or disable the tweak on demand:

If you're interested in giving this a shot, it's available free of cost in Cydia's BigBoss repository right now. The tweak works on iOS 5 and later, all the way up through iOS 8.1.2.

Name: NoKeyPop
Price: FREE
Requirements: iOS 5.0-8.1.2
Tested on: iPhone 5 running iOS 8.1.2
Repo: BigBoss
Developer: PoomSmart