mail.strip_sig_on_reply Setting Is Broken
I've checked mail.strip_sig_on_reply option in my Thunderbird advanced settings and it is still set as true (default) but signatures are not being stripped in replies when they start with -- (dash dash space) above.
Wšykne wótegrona (3)
You're using the right option. I've seen this happen, the signature block detection is not perfect, perhaps the email format (HTML vs plain text) matters or perhaps the signatures are not "-- "? (the space is important).
You are correct, the sig stripping does seem to work only on plain text messages. However, since nearly all messages are formatted these days - including both Yahoo Mail and Gmail - it makes this feature pretty useless doesn't it?
You make a point, I wish this was 100% accurate and worked with all HTML emails :)