Form Calculation from table

In reading the recent article 'More automation possible with table calculation in forms' it shows I can create a Form Calculation that will let me take a sum from a table on the form and insert it into a number field on my form (not in the table).  However, when I click on Add new > Form calculation, it only lets me use elements from the Form, and does not let me choose elements from the Table, as the article shows.  I am using v7.9 on premise if that matters.

Dear Connie,

Looks like you do not use the right 7.9 update
Update with the last one at least the first 2024 version (although it might work with december 2023, not sure for that)
It will do what you are looking for
Best regards
Gilles

Thank you!  I was on the December release, but just updated to the new one and it's working now.  Great new feature!

:-)