Task flow parameters can be used to customize how the task flow behaves, but once the task flow is loaded, how can we interact with it?
Also, how can we communicate between two task flows, or between a task flow and its page container? The answer to all these questions is in contextual events. Contextual events help to solve these questions in an event-driven fashion.
The idea is that one task flow publishes an event and another task flow consumes this event and reacts on it. So, when this event occurs, the other task flow or page can change its behavior without the need to refresh or reload.
You may wonder why this is not mentioned as part of Chapter 7, Handling Events and Partial Page Rendering ...