In Chrome, everything seems to be OK. In Edge the parent does not receive any messages from the Zill popup.
First, make sure the path of 'popup.html' in the scrip of 'test.html' is correct!
Open the test.html in Edge. Click on 'Open popup' and on 'Send message'. The message will be shown in the popup, and it will send a message back. That reply will be visible in the parent.
Click on 'Open zill'. It will open Zill in a new tab. In Chrome you will see in the parent the reply from zill (on screen and in the console). In Edge the parent does not receive a message from zill.