Filtering keys by some text is broken in the certificate list and in the certificate input field (e.g. Encrypt to others).

How to reproduce:

• Filtering in certificate list:
  1. Enter some text in the "Search..." input field above the certificate list
     
     Expected result: Only certificates matching the search pattern are displayed
     
     Actual result: All certificates are displayed
• Entering a certificate in an Encrypt to others input field
  1. Open the Recipients tab in the Notepad
  2. Enter some text in an Encrypt to others input field, so that only a single certificate matches
  3. Press Return
     
     Expected result: The matching certificate is displayed
     
     Actual result: "Multiple matching certificates or groups found" is displayed