title: how do I save changes made in Firefox Developement Edition
body: <p>As I am trying to figure out the 'CSS Grid', I stumbled over Firefox Developement Edition. By the way, a great tool for learning CSS Grid. It would be even nicer if I could use the editor to actually change stuff. Unfortunately, I do not know how to save the changes I made (img).
  help is much appreciated.</p>
  
  <p><a href="https://i.stack.imgur.com/0DAru.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0DAru.jpg" alt="enter image description here"></a></p>