User language setting not applied with FB login

[Cosworth32]

If user has a defined language other than english this setting is not applied when logging in via the FB button. Instead the user has to select the language manually every time.
Logging in normally with user+pass still behaves correctly.

[mnoorenberghe]

Facebook should be detecting the correct language from the geolocation and/or browser settings themselves and since Facebook supports more languages than Webtrees I think leaving that up to them would be better than the module forcing a language on Facebook.