Hello everyone and thank you for your time,
I'm having trouble adding a class to a Save/Create button on a form like so:

After that, the button element doesn't get the class for some reason:

I suspect that the "Save" button changes to "Create" when its creating an attribute for the first time and this kind of renders a new button without inheriting the previous button's class, but then, I tried it out on the Close button which shouldn't change, yet it doesn't get the class as well.
I also tried adding an ID, but I understand it only works for tours and not when rendering the element. Have any of you ran into this problem? If so, have you found a workaround? Any help would be appreciated, thank you.