Love Song other versions

One of the nicest features of Roon is being able to see a list of other versions of a particular track. So, listening to Love Song on Melody Gardot’s Sunset in the Blue, I recognized the lyrics, but at first couldn’t remember where I heard this song before. Not to worry, just click on the blue number indicating other versions. But nothing there rang a bell. Later it came to me: Elton John on Tumbleweed Connection. But his cover (or is it the original?) isn’t mentioned, even though the song’s composer Lesley Duncan is actually singing along! How come he’s overlooked?