select2/docs/_includes/options-new/selections/clearing-selections.html

<section>
  <h2 id="allowClear">
    Can I allow users to clear their selections?
  </h2>
  
  <h3>
    The "x" icon is not clearing the selection
  </h3>

  <h3>
    Can users remove all of their selections in a multiple select at once?
  </h3>
</section>