Disable message "This site has requested that you identify yourself with a certificate:" in Thunderbird

Thunderbird as one(not the only one) annoying feature that it keeps asking you to chose a certificate to identify yourself. The text in the box is: "This site has requested that you identify yourself with a certificate:", then there is a drop-down menu to chose among your certificates, then there is a checkbox that says "Remember this decision", then the buttons "OK" and "Cancel".

Very nice, too bad it asks you for input every single time it needs to authenticate... this is real annoying, it seems the checkbox is there to taunt, because it feels Thunderbird cannot remember your decision...

The solution is simple, but you need to open the config editor "about:config":

• Linux: Edit/Options -> "Advanced" section -> "General" tab -> "Config editor" button.
• Windows: Tools/Options -> "Advanced" section -> "General" tab -> "Config editor" button.
• Mac: Thunderbird->Preferences...->"Advanced" section -> "General" tab -> "Config editor" button.

Search for the entry "security.default_personal_cert" and change it to "Select Automatically" (default value is "Ask Every Time").

This information was collected from mozillazine forum http://forums.mozillazine.org/viewtopic.php?t=652927