Dutch guy here; added the Hunspell dicationairies for both Dutch (Belgium) and French; whenever I open a document with Dutch text, I put all settings (!!) interface, dialogue, spelling etc to Dutch (Belgium). Clicking 'Spelling controle' suggests still all words in English and does not recognize any Dutch word.... In the Spelling Language list, each time Preference reverts to US English. Changing that, does not change the spelling suggestions. Until now, spelling does not let manipulate itself into a different setting; not even after saving the document with all Dutch settings; reopening again all english spelling only.... What to do?
