Hi, a couple of observations.
We use the mermaid plugin to display nodered flows. This does not work in this new or the previous rich text editor. Code is showed as console text:
We could previously work around this by switching the composer back to the older, non-rich text variant. This selection button no longer works.
EDIT: Nevermind. On a full page reload the button starts to work again and in the standard markup editor mermaid works, though not in the rich text version.
Must be a beta-safarism.
(Safari, Mac OS 27 current public beta)