Blank 'Original Graph'

Having completed my Rev.1 “WattsOn” assembly (= IoTaWatt with hardware improvements), I seem to have two faulty CTs, ‘Main’ and ‘HWS’:

The ‘HWS’ (hot-water service) circuit would normally only be switched-on (remotely by my electricity retailer) overnight, so to check if that CT was truly faulty I wanted to view a graph of its power output over the past 12 or 24 hours.
But on opening the Original Graph page and selecting the three power measurements, nothing was graphed. Am I missing some selection to display a graph?

And what are the two tick-boxes next to each selection for?

I fixed the CT problem, so WattsOn is now working as intended. But the ‘Original Graph’ feature still doesn’t work (empty graph).

Since the Graph+ feature does work, I have to assume that the Original Graph feature has now been disabled, which begs the question: why is it still listed in the menu?