Let me see if I understand your question. You would like to be able to sort the series names column, i.e. A, B, C, D ascending or D, C, B, A descending just like you’ve did with the Current column?
As you may know the stacked graphs are re-rendered and ordered when you sort on the columns in the table. So if you click on Current a couple times you’ll see that you’ll hit a state where there’s no sorting arrow - In this case I think that the graphs should order by series name ascending.
Please try this out and let me know if that works