Take a X.509 certificate on a smart card (netkey3.0 if it matters) with the name "Tester, Ted" displayed in the certificate list.
Type "Tester," in the certificate list filter. This will not match that key. "Tester\," will match, as the search is on the user-id string "CN=Tester\, Ted, SERIALNUMBER=3,OU=testlab,O=Some Organisation" and not the display name.

The search string should consider the display name.