Remove Gradient Background

I’d like to grab some screenshots of my model for use on a HMI. For this to work I need a flat colour background.

How can I turn off the gradient background in the model window?

I use an addon that is located in this thread:
https://forums.robotstudio.com/discussion/9456/robotstudio-gradient-backgound

Sorry for the slow response, did look at it but a bit nervous about a dll. How do you install it into robotstudio? and where?