API Reference > imodeljs-frontend > Views > Viewport > onViewedCategoriesChanged onViewedCategoriesChanged Beta onViewedCategoriesChanged: BeEvent<(vp: Viewport) => void> = new BeEvent<(vp: Viewport) => void>() Event called on the next frame after this viewport's set of displayed categories changes. Defined in core/frontend/src/Viewport.ts Line 604 Last Updated: 13 June, 2024