World seed doesn't seem to work correctly

[Stav]

I recently got stuck on a crappy map and before quitting and starting over I thought I'd take a look at the full world by re-generating it in the editor. However, the seeds you enter in the main game don't correspond to the same seed used with the editor. In other words, all other conditions being identical, a seed of "5" doesn't generate the same world using the editor as in the main game. So what's the story with the seeds? Can anyone shed some light here? Thanks.