Why the spell checker works on documents and not on other modules?

We have the latest version of OnlyOffice workspace installed on an Ubuntu 20.04 server.
The spell checker works fine on the document editors.
But it is absent on the mail or the CRM or project modules.
Is there a parameter to set-up to have the spell checker working on all modules?
We are using Brave as a browser but the protection are disabled on our portal.

Spellchecking functionality is specific to document editors. For other modules, you can use your browser’s spellchecking capabilities.
How do I change my language? – Brave Help Center.