https://www.dragthing.com/english/tenyears.html sez “The reason there wasn't much DragThing development between 1998 and 2000 is because I was then part of the team working in secret on the Finder and Mac OS X Dock at Apple. I felt then that the Dock would ultimately replace DragThing. However, for a variety of reasons, I left Apple shortly after Aqua and the Dock were announced in January 2000, and very little of my code survives in the current Dock.”