Are UI choices functional or non-functional requirements?

uml requirements
Michel picture Michel · Jun 2, 2010 · Viewed 10.4k times · Source

Today we had a discussion at the office about UI elements in the required document.

The question is whether a UI requirement is functional or non-functional.

  • "the background must be blue"

Is this a functional or non-functional requirement?

Answer

High Performance Mark picture High Performance Mark · Jun 2, 2010

That is a non-functional requirement, it states how a system is to perform, not what it is to perform.

If this clear distinction is too black and white, too simple perhaps, ignore it or provide a better one ! And, why do you care ?

EDIT: prompted by the other answers. Whether the requirement is functional or non-functional is immaterial to its requirementhood -- if it's a requirement you'd better satisfy it in your product.

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