Charticulator pbviz not accepting a field

[whiteleyrod]

I'm trying to make a Dynamite plot - mean values with whiskers for mean values +/- Standard deviations, - I followed the tutorial here: https://charticulator.com/tutorials/tutorial9.html (Bar Chart with Error bars) but there's a strange glitch.
I am unable to place any value in the "Mean + SD" field well.
The available field wells are mean, Mean - SD, Mean +SD (along with Primary Key)
At first I thought this was because I was using measures (which calculate weighted means for these values), but I've also tried this using columns from the source table, and the same problem exists.
I have tried horizontal as well as vertical bars, and double checked each step from the tutorial, all to no avail.

Here's the .pbviz file: https://1drv.ms/u/s!AgytcDfT4DRFj_kGVfnpM5J89BjqLQ?e=aceqsK and here's a screen capture from both the final Charticulator output, and the available field wells:


Thanks in advance for any help,
Rod