CI Linter does not allow sequence validations

1. Go to the https://gitlab.com/ci/lint
2. Validate example

job1:
  stage: build
  script:
    - execute-script-for-job1
  only:
    - master
  tags:
    - docker

3. Modify it and try to press Validate button

Expected:

Linter should allow you to validate modified example

Actual Result:

Validate button is disabled

Why: So you can try and use linter web page to edit your gitlab-ci files and iterate on multiple errors.