If you set a border at least once, for example for the active state, you will never be able to return to the default value until that state is set. You will need to re-specify the same parameters as for the default state so that the design does not change. It should be possible to simply reset installed settings to their default state. Also, an important note is that we have no way to control the state of :focus on the editor, only using CSS. Video:
https://www.awesomescreenshot.com/video/29302338?key=5000fab5014b78d1a47726ed18410bf9