IIRC you need to change the mode:yaml line to mode:storage
I personally haven’t tried the UI editor because I had it working with yaml before the editor was around. And since it’s already working no reason to change it.
The two options are functionally identical. If you’re new, I’d suggest using storage mode. Indeed, if you’re not using YAML anchors, or secrets, then there’s no reason to use YAML mode, other than momentum (yes, I still use it).
Using storage mode means you can live edit it, and see what you’re getting as you make changes. You don’t get that with YAML mode.
However, yaml mode allows you to maintain comments in the code that ui mode doesn’t.
And yaml mode allows you to split up your ui config using !include statements. Which, if you ever try to edit a large front-end config file in “raw” mode, you will then see the benefit of using !includes.