DIAGGUI: "Add All" button needed on reference control
Similar to the "update all" button, the "add all" button would create new references matching the channels in all existing references, whereas the "update all" button creates references replacing the old references.
We might also consider a modification to the "add" button to allow adding a new reference based on a selected reference.
Motivating use case is "On-off-on" testing, where two references are needed for each channel: the first off, and the on measurement.
Edited by Erik von Reis