Edit: Upon checking K2’s Github repo to share the love, we’ve noticed that this issue will be resolved in the next version of K2.
Edit of Edit: We are still experiencing the issue and no new version has been released yet.
If you are using K2 under Joomla 3.x you might’ve noticed something funky in the categories settings. The labels for the settings don’t display properly. The reason for this is Isis, the template for the Joomla back-end. If you’re using K2 under Joomla 3 you will probably see your category settings looke like below:

To fix this problem, and put both options in one line, you’ll need to add a bit of CSS for K2.
1) Open the following folder: media/k2/assets/css/ and edit the k2.css file.
2) Add the following code to the file, then save it:
div.paramValue label {
display: inline;
}
Save the file, and try refreshing the categories settings screen. The labels will now display in one line, making it a bit easier on the eyes. Please note that when you update K2 this change might be lost.
So great a tip! Thanks a lot.
How come they haven’t fix that mistake so far?
They’ve fixed it on Github, which means it will be solved in the next release. 🙂