I am having trouble getting theme customization form fields to show up in the backend when I use a separate theme customization file. This is what I did. In my theme.yaml file -- I have the following code: form: config/fields.yaml. That works to get the customization button to show up in the backend.

However, I'm not 100% sure how to format the config/fields.yaml file. Currently, this is how I have it set up:

form:
  fields:
    layout:
      label: Layout
      comment: Choosed between a boxed or wide layout.
      type: dropdown
      options:
        stretched: Stretched
        boxed: Boxed

But nothing shows up.

I tried taking out the 'form:' -- still nothing shows up.

Am I doing something wrong?

Try putting your fields directly in your theme.yaml file instead of an external file. If that works, submit an issue to the repository if you think that the theme.yaml file should support external field definitions.

I found the solution -- I need to take out the first line of the code: form:

In other words, the code should look like this:

fields:
  layout:
    label: Layout
    comment: Choosed between a boxed or wide layout.
    type: dropdown
    options:
      stretched: Stretched
      boxed: Boxed

Thank you @moshem17556!

Your suggestion working is wery well.

I think this information is missing in the documentation and should be added asap!

Added in https://github.com/octobercms/docs/commit/5da2764efbdedce368d2e44017fa4e7272da3b28