Since Rails 7 the turbo-rails library is included by default. Turbo Drive intercepts link clicks and form submits. It makes sure that only the <body> part of the page is rerendered instead of the whole page.
This leads to TinyMCE not being properly detached and reattached when a Turbo Drive response is rendered. The textarea will appear without the TinyMCE editor. In this post we expand on the tinymce-rails gem with a Stimulus controller to prevent this issue. The controller helps to reattach TinyMCE and respects the settings in config/tinymce.yml.
If you want to follow along or check out the end result you can find an example respository here: https://github.com/david-uhlig/example-tinymce-rails7-turbo