Thanks @JulianWolf. I thought I had, but I realised I had a typo preventing it from working.
That said, there’s still 40px of margin on the left and right of the screen. This is exactly the same situation that arose with the introduction of the project page module in Connect. It simply isn’t feasible for the type of apps that we develop to have that margin. I can understand 10-20px margin on the left to avoid the weirdness of the sidebar popping out when interacting with the app, however the right margin is a non-starter for us.
Screen realestate is at a premium and this would just look weird with an app like Easy Agile User Story Maps which scrolls left and right. Not everyone has a simple vertically scrolling page which of issues or a config page consisting mostly of text, forms, etc. In this case, the padding makes sense. For us, not so much.
This is what our app would look like with 40px of padding left and right…
I believe these padding settings should be more configurable so we can have the flexibility to ship apps which don’t all have the same use-case, allowing Jira to be used in more scenarios.