User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9b5) Gecko/2008032619 Firefox/3.0b5 Build Identifier: 3.0a1pre (2008050503) At TB3 the default for the settings security.default_personal_cert is set to "Ask Every Time". I suspect that this was taken from FF3 (PSM). The reason in FF was that certificates can be installed without much user interaction and track users with certificates when set to automatic selection (almost like cookies). However TB doesn't have this risk and the default selection should be "Select Automatically" since it's very inconvenient to select a certificate every time a mail message is sent. Reproducible: Always Steps to Reproduce: 1. Configure a SSL/TLS secured mail server and request client certificate authentication. 2. Send a mail through this mail server. 3. Selection of certificate required every time.
You didn't actually need to update to the trunk to get that pain, you could have just updated to 22.214.171.124