System and method for representing an unspecified portion of a measurement system or visually indicating an action required of a user in designing the measurement system. Designing a measurement system may be a gradual process where the user progressively specifies more information regarding components in the system. At any point in the design process, it may be desirable to visually indicate to the user that one or more portions of the system are not yet specified or that the user needs to perform one or more actions. A diagram of the system is displayed, including one or more component icons visually indicating components of the system, and a special icon visually indicating that information regarding a portion of the system has not yet been specified. User input specifying information regarding the portion of the system may be received, and in response, the special icon may be removed from the diagram.