I have been banging my head against the keyboard trying to determine why I was unable to add a “Message” under Forms > Form > Notifications. I saw the message label but no editor appeared:
Turns out, this is due to the Gutenberg Plugin’s “Disable TinyMCE and Classic block” setting:
When I disable this experiment the message field returns, this setting is browser/OS agnostic
The two solutions I can think of is to mark the notification screen as requiring the classic editor, or upgrading it to the block editor. I do see a function in the Gutenberg plugin:
For now I’ve disabled this experiment but as it was a tricky one to debug I wanted to report it here to get it on your roadmap.