Noted by several users: Refresh keys does not work too well.
The status update should be improved and a clear "Done" should be emitted. A nicer, non technical, GUI should probably also be added. E.g. a progressbar with estimated time left. A good (working) cancel button. And a "Details" button that would show the current output of the GnuPG Process. There are also reports of encoding errors.
There is also the wish to refresh a single key in the certificate details and to download all keys that signed a specific key (might be a subtask).
We need to extend GPGME for this to work properly without a GnuPG Process call.