Blue to yellow to vocabulary list does not work

Ever since I bought into Premium the system fails to change blue words to yellow when I click them and does not add them to the vocabulary list. However when I log in on a different computer it all works. Therefore, I think, something did not update in my computer to Premium service. Help!

Hi Rainer,
I am sorry to hear that you have trouble with this. Since it works fine for you on other computer, that means that everything is fine with your account and that something is wrong with your first computer. Would you please try to clear your browser’s cache to check if that might help?