Question When I use Navigation on Button , it doesn't change highlight color.

Hello. I started to learn Unity a month ago. I have a question about Button Navigation(If I have a mistake where I should question, Sorry.). When I use Navigation to manipulate Buttons by KeyBord, Selected Button's color doesn't change highlight color. However, when I select Button by mouse(Don't click just mouseover), it works correctly. Is this Unity's specification? Please give me answer.