When adding custom items, most people will go to wowhead to find the zone ID to use, and put the number they see into the edit box. They will probably expect this to work, because everything in Rarity uses the wowhead IDs.

In reality, the IDs that wowhead uses are NOT correct; Rarity requires using UiMapIDs because that's how the WOW API works. This isn't transparent to end users, and there's no easy way (like, say, going to wowhead) to find out the right number. We could link to the above and create a FAQ for this problem (and I will do so shortly), but it's a workaround and not a fix.

I propose that whenever a map ID is entered, we query the API to find the zone name, check that it's valid (a string value), and display a preview next to the edit box. This way, it will become immediately clear that the ID entered from wowhead is wrong. We can even link to the UI Map ID list in a copy/paste URL box, so that users can go there easily and don't even need to ask in Discord.

Even better: We could add a /rarity mapinfo slash command that can help them make sure the ID is actually correct, by going to the actual ingame location and checking if the ID is what they entered. I've used something like that for debugging and it's useful because there are many subzones with different IDs, but the same map name, so just going by the wowpedia list may yield the wrong result.

(The latter part should likely be a separate issue. I'll add one presently)