On old Reddit, click the coloured line next to a comment to collapse it and all of its replies. You can also click one of the outer lines to collapse a parent comment without having to scroll back up and find it. New Reddit already has collapse buttons. However, if you collapse a large thread, it can leave you much further down the page than you were before. This extension keeps the comment you collapsed on screen, so you don’t lose your place. You can turn smooth scrolling on or off, and choose from a few styles for the comment lines on old Reddit. Works with Reddit Enhancement Suite and subreddit themes on old Reddit. Reddit Comment Collapser is free and open source.