Allow custom Goal field on Ideas portal layout

What is the challenge?

On an internal use Ideas portal, we are unable to add a custom Goals field.

What is the impact?

We prioritize work that is associated to corporate goals. If this information is known at the time of idea submission, this would allow the team responsible for that idea the ability to prioritize the submission if it's associated to a goal.

Describe your idea

The custom Goals field is grayed out as an option when looking at the idea portal layout.