As far as i can see there is no 'capture' scenario, i.e. tell announcer to not broadcast the announcement to all subscribers, but only exclusively to a single one, who requested the capture. In AXAnnouncements there is an 'interception' , using which you can achieve the similar result, except that interceptor is added to each subscription, meaning that you will receive intercepted announcement + additional data as many times as the number of subscriptions registered. Such scenario, as capturing events used heavily in UI, but not only by UI of course. So, suppose we made a Sensor which using announcer to broadcast its events. And there are cases, when you need to get an exclusive capture of all (or specific kind of events) for a single subscriber, without letting them handled using normal flow, until some condition met, when you are releasing capture. Two examples: - mouse capture usually, when you start dragging the stuff, you start capturing mouse events, and release the capture once mouse button released. All widgets, over which you dragging a mouse, should not receive any mouse events, or receive a different event such as 'draggedOver' etc - keyboard focus pass all keyboard events directly to widget which currently has focus - some code examples, by using brute force establishing a loop which consuming all sensor events until mouse button released or key pressed. All of these cases can be supported by adding few things to announcer: - tell announcer to insert a subscriber at the starting of the subscribers list (instead at the end), so it will be first who receive the announcement - make announcer to stop broadcasting announcement down the list, if particular subscription returns false as result of #handle: - when you unsubscribe, things get back to normal without any extra effort and voila.. we can implement a mouse capture, keyboard focus, filtering and event transforming scenarios. -- Best regards, Igor Stasenko AKA sig.