That is misleading, unfortunately, and I believe that the team is aware and has plans to change that in the future. The formula you see is evaluated in the context of the editor. And therefore, the URL is editor.nordcraft.com... But when the formula is actually evaluated in your app, the URL will never be editor.nordcraft.com..., but yoursite.toddle.site or a custom domain. So it will always be false. One way to check if you are in the editor is if you check whether you are running in an iframe. You could have a custom formula with return window.self !== window.parent. But be aware that if your live site is running in an iframe, this also evaluates to true, then.
Hope this makes sense 🙂