API Reference > imodeljs-frontend > Tools > InteractiveTool > onModifierKeyTransition onModifierKeyTransition Method Called when Control, Shift, or Alt modifier keys are pressed or released. onModifierKeyTransition(_wentDown: boolean, _modifier: BeModifierKeys, _event: KeyboardEvent): Promise<EventHandled> Parameter Type Description _wentDown boolean up or down key event _modifier BeModifierKeys The modifier key mask _event KeyboardEvent The event that caused this call Returns - Promise<EventHandled> Yes to refresh view decorations or update dynamics. Defined in core/frontend/src/tools/Tool.ts Line 556 Last Updated: 13 June, 2024