I applied the fix. You put the file down as the special_tab_edit, when it's special_tab_apply that was the file with the content I needed to add to.
Problem is that it won't hold the language change. It will say it's saved the changes, and it does this in the German language phrase, but then reloads in English (as I supposed is the case because I'm using the English language), but the page is still listed as 'English', even though there are no options in the View in Language: option (Not even English). When I reload the page, that's changed back to having only English available. If I switch to German, it's still only English, and forces my language back to English. The article hasn't saved the language settings.
So sumarizing, it seems it won't save the language the article has been changed to, and this may be because I've viewing it in a different language to which it wants, but then I need to to see the article in the first place. Perhaps that's the issue in why it won't save.