Editor Syntax Highlighting not working in Nextcloud version 15 - files_texteditor

In the files_texteditor application, editor syntax highlighting was working in Nextcloud 13 for file types such as php.

After upgrade to version 15 of Nextcloud, the capability appears to be disabled. Tried on pure 15 install, and installation after upgrade from 13. With and without config/mimetypealiases.json and config//mimetypemapping.json files. Before and after issuing occ maintenance:mimetype:update-js.

Does there exist a config or modification to re-enable syntax checking inside the default Nextcloud editor?


Confirmed syntax highlighting does work in Nextcloud 14 for us.

Preview area in 14 also shows syntax highlighting but not 15 up to 15.0.2.