The "Lookup on server" window needs some improvements.
I suggest some progress indication (sometimes the search takes so long that you think Kleopatra maybe hangs) and information where it searches/found or not found something. At the moment if no key was found the user wonders if a search took place at all.
For searching I'd suggest something like "searching for/on WKD..." / "searching on $keyserver..."
In case not found: "No key matching the search criteria was found via WKD and keyserver $keyserver"
In case keys were found I'd like to see the the origin of the keys if I have the column "origin" displayed. It would help to choose if multiple candidates were found.
Additionally I'd like some hint for the uninitiated what "x certificates without name and mail address where ignored" means resp. where information regarding this message can be found. Maybe a tooltip?