Page blueprint form data not saved to pages frontmatter

Hi,

I am creating some custom page blueprints, but I am having problems with saving the form's content. In this example, I am adding a new tab called some_tab with a simple text field on it, but no input is being persisted on the page's frontmatter.

title: Case
'@extends':
    type: default
    context: blueprints://pages

form:
  fields:
    tabs:
      fields:
        some_tab:
          type: tab
          title: Some Tab

What am I doing wrong here?

Thanks,
Babs

Got it... when the field name is prepended with header, the content is save to the frontmatter. RTFM...