It's only shown after you sort the Playlist differently. It's not available for AutoPlaylists.

Sorry, but can you elaborate? When I right click on a Playlist, I don't see the option you mention. Is this something that has to be configured?

That's it! Thank you. I was highlighting all the tracks and right clicking.

right click on the playlist, update play order. Not a script or addon, its basic funcionality

Seems to me there used to be a function or script where you could rearrange a regular playlist, such as alphabetically, and then click something that would update that current sort order. Can anyone point me in the right direction?