XCode: Enter edit mode in numeric up/down box

Question

I am using the attributes inspector in XCode (7.2) to change some values of a SpriteKit element. When I press TAB the numeric up/down box is highlighted (see image below), but when I start typing the new value, all that happens is that my mac makes a disgruntled noise. So the question is: How do I enter edit mode of this box without using the mouse. I have tried pressing Enter, but to no avail.

Answer 1

This is simply an error of the SpriteKit and I do not believe that there is another way to do it without using the mouse because of this. However you can try holding down the mouse button to change it by larger increments or just double click it.