How can I add a colour style to the existing ones?

I would like to create a new colour style that will be added to the existing ones. Before the update of the variable - I was able to do it with the + button - but now it’s asking me to add a variable, which is not adding the colour style to the existing library. How can add it to the existing library, to live in the same place as the others?

It seemed to be a bug that is gone