My editing troubles are solved.
With the last redesign and so far, I could post almost everything (formatted text, hyperlinks, pics, videos, etc.) because my IE8 opens a version of the new mobile editor.
But that did not happen every time I needed to edit a reply of mine to a post by someone else. In such a case, I always got this poo:
And if I did try to edit nevertheless by clicking "Publish", I always got this other poo:
All that poo till this evening, when I was trying to edit a reply to a post (you should never stop trying!) and I had the idea of right clicking the "edit" pop-up menu voice, and then choose "open in a new tab"... Lo and behold... I got THIS!
And that is the "best new editor", that works for me. I tried that trick several times, and it always works. Kinja, I won.