I've just added a new signature in Thunderbird and when I go to send a new message it has a bunch of red lines around the layout of the signature, probably because it's within a html table.

Now I know when I send the message the receiver won't see these lines, however it is still annoying and I would prefer to see the signature properly rather than it look like something you should only see when in "preview" mode or something.

Here is an example:

enter image description here

Is there any way to remove this red outline and get it to display the signature the same way it will be received?

1 Answer 1


You could try this:

In userContent.css:

table[border="0"] > tr > td, table[border="0"] > tr > th,
table[border="0"] > thead > tr

From: http://forums.mozillazine.org/viewtopic.php?f=39&t=605884

It's an old one, but if there still is userContent.css file, you could be able to edit it to change the table borders. Might be userChrome.css nowadays. Can be found in your profile folder under chrome folder. If not found, you can create it.

  • Is that the full code needed? Looked at the link and it seemed to have a lot more code.
    – Brett
    Jun 12, 2018 at 14:59
  • Not quite sure. I cannot test this right now. Basically the point is that you can use css to modify the look and feel of TB. Jun 13, 2018 at 13:40

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