The tooltip says "Search for certificates online using a public keyserver".
This is usually wrong in GnuPG VSD, as the default is to search in the AD. It is right most of the time in Gpg4win, where the default is a public keyserver.
It's probably not possible to display different messages based on the actual setting for keyserver in dirmngr.conf. Therefore I'd suggest just "Search for certificates at the configured server".
See T6664 for the other issue mentioned here before.