Quick question Monks, how would I conditionally apply the "Required" constraint to an element. I thought using the "when" method would do it, but my element definition is being rejected. Here is what I'm trying so far.

    - type: Textarea
      name: pdc
      label: Comments
      cols: 60
      rows: 4 
      constraints:
        - Required
          when:
            field: pd
            value: 1
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Error:

*.yml: YAML::XS::Load Error: The problem:

    mapping values are not allowed in this context
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Any ideas on what I'm doing wrong?
Many thanks.

EDIT: This is the solution.

      constraints:
        - type: Required
          when:
            field: pd
            value: 1
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It required some experimentation on my part, but if someone here knows where in the docs something like this might be explained, they should probably post a link for future reference. I would imagine it's in one of the FormFu docs, or possibly even the Config::General docs (could not find it myself).