API Reference > imodeljs-frontend > Views > ChangeFlags ChangeFlags Class Describes which aspects of a Viewport have changed. Each time Viewport.renderFrame is invoked, the aspects of the viewport that have changed since the previous call to renderFrame are computed and dispatched via the Viewport.onViewportChanged event. Properties Name Type Description alwaysDrawn Accessor ReadOnly boolean The set of always-drawn elements has changed. areFeatureOverridesDirty Accessor ReadOnly boolean Returns true if any aspects affecting FeatureSymbology.Overrides have changed. displayStyle Accessor ReadOnly boolean The DisplayStyleState or its settings such as ViewFlags have changed. featureOverrideProvider Accessor ReadOnly boolean The FeatureOverrideProvider has changed, or its internal state has changed such that its overrides must be recomputed. hasChanges Accessor ReadOnly boolean Returns true if any aspect at all has changed. neverDrawn Accessor ReadOnly boolean The set of never-drawn elements has changed. viewedCategories Accessor ReadOnly boolean The set of displayed categories defined by the viewport's CategorySelectorState has changed. viewedCategoriesPerModel Accessor ReadOnly boolean The PerModelCategoryVisibility.Overrides associated with the viewport have changed. viewedModels Accessor ReadOnly boolean The set of models to be displayed in the viewport has changed. viewState Accessor ReadOnly boolean changeView was used to replace the previous ViewState with a new one. Defined in core/frontend/src/ChangeFlags.ts Line 32 Last Updated: 29 November, 2022