When they're done, they unrar and leave the list. If they're still in the list, they're not done. If they don't leave and there are pars. You can right click "Properties" and see a status window for the current PAR state.
You do know you can click the arrow/plus sign and see all of the files that make up the set?
You might want to give 6.01B6 a try. It displays more information in the download list.