As Paul says, the problem is your own content design, in this case the J2Store content menu.
Before you can show or hide the menu, you need to set it in the J2Store category.
Add a hint element image.
Joomla is rarely used in Japan, so you have to solve it yourself.
I had a hard time with it, but I was able to get a rough idea of what would happen with the quick start.
Hope this helps.