If the overlay window had the same selection as All SPL tab when opened I would find that very beneficial as a time saver, mentioned a page or two back in this thread.
Somewhat related to workflow efficiency, I think it would be great to have the IR window settings of previous measurement, or perhaps the selected measurement applied to new measurements. Currently new measurements get default settings set in preferences requiring selection of previous measurement, then "apply windows to all" to make sure all measurements are using same window settings.