You have to make parent subforms Flowed and check Allow Page Breaks within Content option. Then in the layout of text field you should check Expand to fit in the height area. After you exit the text field it expands and flow to the next page if needed.
I'll describe the way I'm using.
You have to make parent subforms Flowed and check Allow Page Breaks within Content option. Then in the layout of text field you should check Expand to fit in the height area.
After you exit the text field it expands and flow to the next page if needed.
Regards, Andrey