"Edit Hook" > "Display Rules" > "Category" can't be chosen

Hello,

As the title says "category" can't be chosen - when I click the "page category" option (I'm seeing the JA translation and not sure what exactly it is in En though), it automatically adds all the categories and there's no option to pick one or some. Seems like the "choose" dropdown menu does not function.

Here's the screenshot: https://prnt.sc/10l8r8p

There's a "choose" word but it's just plain text. I made sure my theme is up to date.

Best,
Shunya