formAssociated bug firefox

HTML

<x-element>
'highlight and drag me'
</x-element>

JavaScript

class element extends HTMLElement {
  static get formAssociated() {
    return true;
  }
  
  constructor() {
  super();
  this.addEventListener('dragstart', () => {
	  console.log('dragged!')
  })
  }
  
}

customElements.define('x-element', element);