Forwards notification messages to all owned components.
procedure Notification(AComponent: TComponent; Operation: TOperation); override;
Do not call the Notification method in an application. Notification is called automatically when the component specified by AComponent is about to be inserted or removed, as specified by Operation. By default, components pass along the notification to their owned components, if any.
A component can, if needed, act on the notification that a component is being inserted or removed. For example, if a component has object fields or properties that contain references to other components, it can check the notifications of component removals and invalidate those references as needed.
Notification is not called for components that are freed implicitly (because their Owner is freed).