Per https://www.mediawiki.org/w/index.php?title=Topic:Thapndnvwxb6j1kt&topic_showPostId=thapndnxh3puza9p#flow-post-thapndnxh3puza9p .
I was able to create a new page in VE in Chrome, and to edit it in Opera. After this, nothing happens after clicking on Edit, while clicking on Edit source loads the wikitext editor without a toolbar.
(Seems UBN! to me, apologies in case you disagree.)