- Connected, enable the new editor in preferences https://fr.wikipedia.org/wiki/Sp%C3%A9cial:Pr%C3%A9f%C3%A9rences#mw-prefsection-betafeatures
- Go to https://fr.wikipedia.org/w/index.php?title=Utilisateur:Nyspelache/Brouillon&action=history&uselang=en
- Click on one of the undo link
Actual behavior
Good old wikitext editor is loaded. Help is printed on the top : The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then save the changes below to finish undoing the edit.
Excepted behavior
The new wikitext should be loaded instead of the old one.
It's just like the hook for this event was not taken into account by the extension.