I have created English-Chinese flashcards, importing from a txt file with English headwords. Since I have purchased 21 Century E-C dictionary, the Mandarin definition was given by the program. Selecting organize cards command I see all the flashcards in a new category. Unfortunately starting a test with E-C flashcards selected, Pleco responds that there are no cards in this category. Of course I have enabled E-C flashcard in Settings/Flashcards. What is the problem?