On the new nice interface, when I click the search button, nothing happens. Any setting required?
I never used the CT frequent words option, but I do use AntConc. The main advantage for me is, that you can delete stopwords in one go. For you - Masato - it might be important that the developer, Laurence Anthony, works at a Japanese university, there are even tutorials in Japanese. So I suppose Japanese can be handled by it.
Please see the menu Task > Frequent words > Add frequent words to glossary (the option). By default, they are added to translation memories.