My Drupal was installed in English and Spanish as added language, because I prefer to be able administer in the site in English. Spanish is set as the default language and Language negotiation is set to Path prefix with language fallback. The default language of the Firefox 4 browser is set to English as first language and Spanish as second. The user has English as his language.
When the interface is set to English by removing the es from the URL. As a result I see the whole page of Display Fields setting in core page content type at admin/content/node-type/page/display in English except the sub tabs, they are still in Spanish.
They are: Básico | Buscar | Comodín | RSS
After doing some experiments I noticed that you can only see these tabs in the original language when you set English as Drupal's default interface language. So it seems that the code responsible for these sub-tabs only looks at the default language setting and not the presently active language.
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