ZenDesk Private Comment By Default

zendesk.user.js

// ==UserScript==
// @name         ZenDesk Private Comment By Default
// @namespace    greatghoul
// @version      0.1
// @description  ZenDesk Private Comment By Default
// @author       greatghoul
// @match        https://*.zendesk.com/*
// @grant        none
// ==/UserScript==

(function() {
  document.addEventListener('click', e => {
    if (e.target.classList.contains('track-id-publicComment') && e.target.classList.contains('btn')) {
      e.target.setAttribute('data-click-mode', 'manual')
    }
  }, false)

  window.setInterval(() => {
    const btn = document.querySelector('.btn.private_note:not(.active)')
    const isManualMode = document.querySelector('.btn[data-click-mode="manual"]')
    btn && !isManualMode && btn.click()
  }, 300)
})();