You can very much draw a border on a windows and a "close" button without any libraries.
Usually, I'd understand if you're lazy and can't be bothered and just pull in some dependency to do it for you, but if you're implementing a toolkit, this is the kind of thing that is SHOULD provide.
Usually, I'd understand if you're lazy and can't be bothered and just pull in some dependency to do it for you, but if you're implementing a toolkit, this is the kind of thing that is SHOULD provide.