What makes map issuers show up?

Hello, sorry if this has been asked before, but spent awhile looking through the forum and didn't find an answer.

What is the trigger that makes issuers show up on the map? One obvious one is that if you have a coin from that issuer, it pops up on whatever the modern country is. Eg. I have 3 coins from “India - British” show up under India when I hover. Makes sense.

However, I don't understand what is triggering some issuers to show up with Zero coins. For example, hovering over Guernsey shows “Alderney: 0 coins”, and hovering over Puerto Rico I see “Puerto Rico: 0 coins”. Not that I don't appreciate the inspiration, but seems odd especially given how many clearly don't show up.

(My related pet wish is for currencies to show up bulleted under issuers if relevant, eg. separating Euros and pre-euro coins, but perhaps that's for the future!)

Thanks for your help!

What triggers an issuer in your map is:

A- having a coin of said issuer;

B- having a coin of a related issuer.

Starting with Puerto Rico that is easier to explain: Puerto Rico is an issuer but it is also part of the United States, so having any US coin will light up Puerto Rico and a few other spots on the worldmap (Hawaii and some Pacific islands).

This also applies to Alderney. It is part of the Bailiwick of Guernsey, so having a Guernsey coin lights up Guernsey and Alderney.

Another example: Greenland is an issuer but it is Denmark's territory, having any Denmark coin will light up Greenland and also Faroe islands.

This also applies to older issuers; having an Ottoman, Roman or Soviet coin lights up all the countries that were part of their territory, even if you don't own any coin of certain modern country.

In this case hovering your mouse will show as (example):

Ottoman Empire: 1 coin

Egypt: 0 coins

I hope you understand my explanation.

Others may give better answers if you still have doubts.

I'm not talking about the lighting up, I'm talking about the displaying of issuers. Puerto Rico is displaying, but Hawaii isn't.