Disabling Typo3 form element validator

Question

Field Message is mandatory when you choose "Need Message" I'm hiding the field with javascript when no is selected. I want the span required (*) to be present Everything's fine at first step You choose "NO" validator is disabled, "YES" validator do is job Problem is when you return from summary page, validation is ok but field is no more mark as mandatory (I want "required" span to be present). (Span is rendered on validator value, not on required: required) What I'm I doing wrong? How do you guys do for conditional validations?

Form Image

Of course I could solve the problem with javascript but I would like to understand :-)

renderingOptions:
  submitButtonLabel: Soumettre
  fluidAdditionalAttributes:
    novalidate: 'novalidate'
identifier: simpleA
type: Form
label: 'Simple A'
finishers:
  -
    options:
      subject: 'Your message: {subject}'
      recipients:
        [email protected]: 'Test Company'
      senderAddress: [email protected]
      senderName: Tests
      format: html
      attachUploads: true
      translation:
        language: default
      title: 'Confirmation'
    identifier: EmailToReceiver
renderables:
  -
    renderingOptions:
      previousButtonLabel: 'Previous'
      nextButtonLabel: 'Next'
    identifier: page-1
    type: Page
    label: 'Test Form'
    renderables:
      -
        properties:
          options:
            1: 'No'
            2: 'Yes'
          fluidAdditionalAttributes:
            required: required
        type: SingleSelect
        identifier: sel-message
        label: 'Need Message?'
        defaultValue: 1
        validators:
          -
            identifier: NotEmpty
      -
        defaultValue: ''
        identifier: message
        type: Textarea
        label: Message
        properties:
          fluidAdditionalAttributes:
            required: required
            placeholder: 'Your message here...'
        variants:
          -
            identifier: varMessage0
            condition: 'stepType == "Page"'
            label: 'Message 0'
            validators:
              -
                identifier: NotEmpty
          -
            identifier: varMessage1
            condition: 'formValues["sel-message"] == 1'
            label: 'Message 1'
            validators: []
          -
            identifier: varMessage2
            condition: 'formValues["sel-message"] == 2'
            label: 'Message Included'
            validators:
              -
                identifier: NotEmpty
        validators:
          -
            identifier: NotEmpty
  -
    renderingOptions:
      previousButtonLabel: 'Previous'
      nextButtonLabel: 'Next'
    identifier: summary
    type: SummaryPage
    label: Summary