In lots of my OutSystems projects I came across master-detail data structures. This sample app consists of a core service to manage purchase orders and their related order items and an user interface module demonstrating a pattern for locally editing sub items (here: order items) via a popup dialog. Also it implements a paginated list view with search functionality and SQL-injection-safe dynamic sorting.
This Forge component is accompanied by three articles explaining its construction step by step, so that you can recreate the example and comprehend the solution yourself: