A noob - but, I have two possible answers - first one, is create variable/reference to each of the widget classes inside each other (if there is only one of each, then this is easier). This is the simplest (completely BAD coding way of doing it… especially if you use a “all actors of class” X approach.
The better (?) alternative would be to create an interface (especially if it’s one way traffic) where you send a message from one widget and it’s ‘heard’ by the other widget. The thing I’m not entirely comfortable with is that to send messages you either need to specify the actor you’re sending it to (in which case why not just reference it directly) - or you grab all actors that use that specific interface (which might just be one). I’m sure others will provide better answers (I AM a NOOB after all).