Let's says inside my external settings URL 

I send my data to my Weebly app

if(message.action === "settings:load"){
           
            const settings = {
                action: "settings:update",
                data: {
                    question: "my new question"
                }

            }
        
           parent.postMessage(settings, window.frameOrigin);
}

Now how to capture the event that the question attribute has been updated from that external setting inside editor_element.js

I tried 

this.settings.on("change:question", function(model, name) {
                console.log("question change")
              
})

And the only way I found to make it works is to set it inside my editor_element.js file which doesn't resolve my issue

this.settings.set("question", "John Doe");

I want to be able to set settings from my external URL file and capture change inside my editor_element.js