Sorry, but nested portals are not possible in any current version of FileMaker. I think that you are setting up Need layout solution for nested portals... portals where two separate (not nested) portals are set up side by side. Clicking a portal row in the Master portal updates a relationship to show the associated detail records in the detail portal. That sound right?
When a screen fails to update until you click a blank area of the layout you have a situation where your layout is not updating until whatever change to your data is committed by a commit records event. There is a script step for committing records that you can include in your script to get things to update without needing to click a layout background.
You're right, it's from your 12/18/2012 reply to a question.
The screen doesn't fail to update, it's working fine. The grandchild portal updates perfectly when I click the button on the associated row of the child portal its just that that action doesn't cause a reformatting of the selected child row. Only touching the fields or background causes the reformatting. I want the row to reformat with the button push.
Like I said, sounds like you need a commit records step.
I've had the Commit records step in the whole time between 'Set Field' and 'Exit Script' (see image). Interestingly, the format (yellow background) does show as long as I have the button 'held'. As soon as I let off the trackpad the formatting goes away. And like I said the rest of the functionality i.e. picking the right set of records for the grandchild portal is working well.
(First time sending an image, hope it comes through...)