Hi,

Justin here with the support engineering team

Thanks for getting in touch about the feature you're looking for!

The side panel URL input in Front is static and is the URL where you will host your plugin application. Context updates can be used in tandem with the Context API, though, to open a URL or open a URL in a popup. I realize this is not the method you had hoped to achieve this with but perhaps these functions could help your team achieve the desired results. 
 

Although Front doesn't currently offer this as you’ve described here, we have our Product Ideas Portal where you can submit requests for features you need. If you see another feature you'd love, just upvote it there and our team will see the tally.

Our Product team reviews these ideas every week. You'll receive an email update if a feature you submit or upvote is developed and shipped.

We really appreciate your feedback — thank you for taking the time to send it!
 

If there are any other questions, please do not hesitate to reach out!

Thanks, 
Justin