There should not be any difference between FMP 12 and 13 for such a script and I use similar scripts in FMP 13 without issue.
The script shown does not look like the entire script. Can you post the entire script. If it is the entire script, please explain how setting a single field results in populating all the fields in the layout above the portal.
I assume by "icon" you mean button with a script attached. Is this the actual script? If so, what does the second step do? If the first step always sets the field by the value of the other field and it's always the same other field, then why not have the field referred to in the portal in the first place?
That was the entire script. Weird I have both of those in the script and it works in version 12. I now got it working in version 13 but only use
But surely you know how your own database works?
I can guess but was asking for clarification. Presumably you have a relationship that works off the GMDate field via a relationship based on that field. This might be a look up or just a link to that related data.
The presence or absence of a step that sets a variable to the active portal row number shouldn't have any affect one way or the other on what data appears in those fields.