Why the limitation to a single OpenPGP keyserver?

Because otherwise the UI will get confusing if you get the same key
e.g. from multiple keyservers And it is AFAIK a limitation of GnuPG.
We could use a keyserver with a DNS entry again which randomly selects
a keyserver? To avoid always using the same one.

Actually, when having multiple keyservers, the following would work:

My suggestion would be the following:

Is the lack of display of entries in the listbox proper functionality?