I hope you're doing well, Majordave.
The pop out icon in the map section when adding mileage in QuickBooks Online is currently unavailable. While we’re unable to get this option at the moment, you can send a feature request by clicking the Gear > Feedback. Other users might also have the same request.
Here's a sample screenshot:
Meanwhile, I’m adding these articles to get more insights about the mileage feature:
You can also visit our QuickBooks Blog for the latest news and feature releases.
Please, feel free to add a reply here if you have any follow-up questions or other concerns. Stay safe!