How can I enable asian phonetic guide in LibreOffice 7?

I am trying to use the asian phonetic guide for japanese text, I am able to see the asian phonetic guide in my text toolbar but it is disabled, I am going in to:
Tools>Language>For All Text>More…>Language Settings>Languages>Defaukt Languages for Documents
I am selecting the checkbox Asian and Japanese in the dropdown.
Click OK in the dialog box, but when selecting japanese text in the document the asian phonetic guide still remains disabled.

(edit: activated screenshot)

Try a third-party extension like this one.