I believe they used a different one at one point and then a couple years ago switched to tinymce. You can find out more by searching their support forum: https://xenforo.com/community/resources/tinymce-quattro-and-its-wysiwyg-bbcodes.1881/ I don't know maybe I didn't read it right then. I was looking something up regarding tinymce and stumbled across a thread where one of the xenforo guys was saying something like: "tinymce makes our forum look more attractive and provides a better user experience". Some users were whining that they didn't like the switch to tinymce. But maybe I got it all wrong.