I have attached 2 files to the OP (rename the script file to ".lua" first).
Since this is the most basic example, I feel something must be terribly wrong in my editor / model / script.
Yes, the (nested) editor uses absolute grid orientation (ABS), switching to REL shows the position of the currently selected group as (0, 0, 0).
Switching back to ABS shows the position of the first item of the group again.
Even though the bottom right in the editor always says '(rel) grid position X; Y; Z'
Since this is the most basic example, I feel something must be terribly wrong in my editor / model / script.
Yes, the (nested) editor uses absolute grid orientation (ABS), switching to REL shows the position of the currently selected group as (0, 0, 0).
Switching back to ABS shows the position of the first item of the group again.
Even though the bottom right in the editor always says '(rel) grid position X; Y; Z'