Firstly, enter any key to display all countries with no official currency, then, secondly, enter as many currencies as you can, and the map will be filled with the countries that use them.
That's a bit like saying one should accept sun for the Peruvian sol, or dollar for the Samoan tala. Crown is the literal translation into English (eg in Swedish, Kungen bar sin krona - the king wore his crown), but that's not the names of those currencies.
Probably when you updated your quiz, you kept the "Croatian Euro" separated from all other Euros. It seems that the quiz has two "Euro" answers, and when you type one of them, the other doesn't necessarily light up.
Weird quirk - it accepts "schilling" as a type-in for shilling for Kenya, Somalia, and Uganda, but not Tanzania. And if you type "schilling", it displays "shilling" as having been guessed in the list. I knew that Tanzania used shillings, knew I'd given that answer, and the list showed that I'd guessed shilling, but Tanzania still showed unguessed on the map. So you have to spell it right for Tanzania (but not the others), but once you've entered the incorrect spelling, you would never guess the correct one, since the correct spelling is already displayed as having been guessed.
it doesn't matter much, especially in this quiz, but I prefer it when you have to type any NUMBER ([0-9] I think in regex) to get the ones with no answer. this means that if you type euro and press enter you can see what answers it corresponds too without having the 'no official..' appear every time