Colored Quote Bars

It has long annoyed me that Thunderbird sometimes treats the '>' characters in excerpts from diffs as reply markers and draws a blue line instead of the actual characters from the E-mail.

I finally found some talk about how to disable that feature ​here.

Put this in ~/.thunderbird/*.default/chrome/userContent.css:

  blockquote[type=cite] {
    padding-bottom: 0 ! important;
    padding-top: 0 ! important;
    padding-left: 0 ! important;
    border-left: none ! important;
    border-right: none ! important;
  }

Set the following options:

  user_pref("mail.quoted_graphical", false);
  user_pref("mailnews.display.disable_format_flowed_support", true);

And the bars go away. Along the way, I noticed that if format=flow is included in the Content-Type header, Thunderbird does the right thing. So, the source of these E-mails is partly to blame, but I am happy that there is something I can do about it for now.