Benjamin Leong worked on the LifeSG/react-design-system repository, focusing on improving the reliability of the calendar component. He addressed a bug where dates were not hidden correctly when the 'activemonthday' type was present, which previously led to inconsistent date visibility and user confusion. By refining the component’s display logic in React and TypeScript, and applying precise CSS styling, Benjamin ensured that the calendar now hides dates according to the 'type' prop as intended. This targeted fix enhanced UI predictability, brought the component in line with design system guidelines, and improved maintainability by isolating and clarifying the relevant logic.