May be because your using firefox in Full screen mode, restore to older version

• https://support.mozilla.org/en-US/kb/restore-menu-bar-firefox

j'ai fait les 2 vérifications du lien donné avant de publier la question!

Could you share the screenshot.

voici

This is a known bug on Catalina where you only see the Firefox menu label and all other labels are missing.

• Bug 1603956 - Racing for the same prototype document causes others to receive an untranslated prototype and then cache it

(please do not comment in bug reports
https://bugzilla.mozilla.org/page.cgi?id=etiquette.html)

je suis sur high sierra

comment regler le pb?

les menus de firefox apparaissent quand les fenètres de firefox sont réduites