In the Java Plug-in Control Panel - Certificates - Signed applet - It is possible to have duplicate names in the listbox since only the Subject CN field is used for the name in the listbox. For example only Sun Microsystems Inc shows up in the listbox for both verisign and thawte certificates. The issuer (ex: VeriSign, Inc) should also be included in the name. An example of what should be in the listbox: Sun Microsystems Inc; VeriSign, Inc