title: Error: no DISPLAY environment variable specified
body: <p>I have set up one Selenium Grid with one Hub in Ubuntu Server and one Node in Ubuntu Desktop. Installed Geckodriver and Firefox on the Node machine. And using the following python code.</p>
  <pre><code>from selenium import webdriver
  from selenium.webdriver.firefox.options import Options as FirefoxOptions
  
  options = webdriver.FirefoxOptions()
  driver = webdriver.Remote(
      command_executor='http://192.168.56.7:4444/wd/hub',
      options=options
  )
  </code></pre>
  <p>But getting error <strong>Error: no DISPLAY environment variable specified</strong> on the Node machine.</p>
  <p>Working exactly fine after adding</p>
  <pre><code>options.add_argument('--headless')
  </code></pre>
  <p>Don't want to run it in headless mode.</p>
  <p>Thanks to all in advance.</p>