allowImplicitScrolling property
override
Whether a viewport is allowed to change its scroll position implicitly in response to a call to RenderObject.showOnScreen.
RenderObject.showOnScreen is for example used to bring a text field fully on screen after it has received focus. This property controls whether the viewport associated with this object is allowed to change the scroll position to fulfill such a request.
Implementation
@override
bool get allowImplicitScrolling => false;