How to listen to custom events on all windows, bubbling issue?

Question

ok, now i see what you mean, but according to MDN you need to use this:

document.addEventListener("MyExtensionEvent", function(e) { myExtension.myListener(e); }, false, true);
// The last value is a Mozilla-specific value to indicate untrusted content is allowed to trigger the event

source: https://developer.mozilla.org/en-US/Add-ons/Code_snippets/Interaction_between_privileged_and_non-privileged_pages

I tested it and it works!

web page:

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>

    <div id="main-content"><button onclick="trigger()">Trigger custom event</button></div>

    <script type="text/javascript">

        function trigger(){
            var myEvent = new CustomEvent('peakAhBoo', {
                'detail': {
                    'hazcheeseburger': true
                }
            });
            var myEvent = window.document.createEvent('CustomEvent');
            var myEventDetail = {hello:'world'};
            myEvent.initCustomEvent('peakAhBoo', true, true, myEventDetail);
            window.dispatchEvent(myEvent);
            console.log(myEvent)
        }

    </script>
</body>
</html>

and in privileged code:

function respondToCustomEvent_peakAhBoo(e){
    console.log('g: '+e.target);
}

gBrowser.addEventListener("peakAhBoo", respondToCustomEvent_peakAhBoo, false, true);