Trouble getting vanilla maps into map editor

Hey gang!

I tried editing one of the new Sunset Harbor vanilla maps (just for personal use) and I'm not getting it to be selectable for loading.

I copied the map from the base game folder to my user folder (double-triple checked that it's the correct one) but the map is not showing up to load in the editor. I tried changing the file name just to be safe, but no change.

I also tried temporarily moving all other map files in my user folder to somewhere else entirely, just leaving the vanilla map in there by itself. The load button for Map Editor got greyed out, as if the folder was empty.

Any ideas what's going on here?

Thanks!