Why do red lines appear inside and around my signature in Thunderbird?
Red lines appear inside and around your email signature in Thunderbird because Thunderbird displays visual guides for borderless HTML tables inside its message composition window.
How HTML signatures are structured: Your MySignature email signature is built using an HTML table with a border size of 0 pixels so the grid remains invisible in emails.
Why Thunderbird displays red outlines: In Thunderbird's Write (compose) window, Thunderbird highlights all 0-pixel table rows and cells with red lines so you can see where table boundaries are located while editing.
Normal behavior: These red borders are a visual editing aid built into Thunderbird and do not indicate an error in your MySignature design.
Will my email recipients see the red borders?
No, your email recipients will not see the red borders in received messages. Because the HTML table in your MySignature email signature has a 0-pixel border size and the red outlines are not part of the actual HTML code, the red lines disappear automatically when you send the email.
Expected outcome: You can compose and send emails in Thunderbird normally - recipients will see your clean MySignature layout without any red lines.
Why does "--" appear above my signature in Thunderbird?
The two dashes (--) that appear directly above your email signature in Thunderbird are a standard signature separator (delimiter).
Purpose: The -- delimiter tells email programs where the main email body ends and where the email signature begins.
Benefit in email threads: When recipients reply to your message, many email clients use this delimiter to automatically strip out the signature block below it, preventing multiple duplicate signatures from piling up in long reply chains.
Need more help?
If you have other questions about setting up or formatting your signature in Thunderbird, check our Knowledge Base for more articles, or contact our Support Team via live chat or email.