Hi,
IIUC, making it impossible in Kleopatra to certify more than one key ID at once was a deliberate decision. However, there’s a working checkbox in the “Certify Certificate” dialogue that can confuse the user and mislead them into thinking that this is actually possible (the checkbox’s outlined in red in the image below).
So perhaps the checkbox should be removed or, if there are plans on implementing certifying more one key ID, at least be greyed out for now.
Kleopatra ver. Gpg4win-5.1.0.

