To edit multiple elements with a single value

Use the same field identifier for multiple control plug-ins to treat two or more fields as a single editing element that will receive the same value.
This can for example be used with a bar that scales and a text label that shows its value. The scale value and the text can then be set in a single operation, ensuring that there is no mismatch between the bar size and the written text value.

Viz Trio User Guide