Jan Henrik Overland enhanced the dhis2/line-listing-app by enabling the Organization Unit Tree for user-selected units, focusing on improving the frontend component’s usability and accuracy. He updated the JavaScript codebase to support dynamic rendering of the OU tree, ensuring that analytics views reflect correct filtering and decimal formatting when users select organization units. To maintain reliability, he revised and expanded automated tests, aligning them with the new behavior and safeguarding against regressions. His work centered on frontend development, JavaScript, and testing, resulting in a more intuitive data selection experience and reducing the risk of misinterpretation in analytics filtering scenarios.