Adding subrace to custom race

[DrBartleby]

I've created a race and am attempting to add some subrace selections to it. However when I do the new race doesn't have a Subrace field in the Race tab for character creation.

If I add the subrace as a subrace for an already created race (like Elf for instance) it shows up fine but when selected it has the red text "You may only choose one subrace".

Does anyone know of any special trick to making a subrace appear for a custom race?

I feel like I'm missing something from the creation process.