I received this question via e-mail and wanted to answer it here for others to see also. One reason why a lookup table wont work is your lookup table status. Once you populate your lookup tables there is a option down on the bottom called "read only". In order to see the lookup table grip once you close the block editor this read only option needs to be set to "Allow reverse Lookup". When ever you add a lookup row or sometimes modify some values it might pop back as read only. So, make sure to glance down when your done editing your lookup table to make sure the allow reverse lookup is checked.