Floating Table of Contents

It would be nice to have an option within Confluence's TOC macro that lets users choose if a TOC floats or not, i.e., follows the user as they scroll up/down a website,

Atlassian seems to have a rather neat floating TOC on its own [documentation|https://developer.atlassian.com/server/confluence/creating-a-new-confluence-macro/,|http://example.com]%2C/] although I wonder if the website on that particular URL is a Confluence instance?