The background color of the Folder and Threads Panes can be set with this userChrome.css:

#folderTree,
#threadTree
{
  background-color: #90ee90 !important;
  color: black !important;
}

#abResultsTree {
  -moz-appearance: none !important;
  background-color: #90ee90 !important; }

Create a subfolder of the profile folder named chrome, and in chrome create a userChrome.css file with a text editor, with the above code. The second part colors part of the Address Book and the Contacts Sidebar.

Thanks sfhowes. That changed some of the colors.

In the folderTree every second line changed the color, see attachment. That is true for all my 14 accounts, and even for those that do not have localized folder names in it.

The threadTree seems to be ok.

The results-tree (I suppose that is where the mail contents are shown) did not change at all. Plain mails are just black on white.

And it looks as if parts of the system theme are still active (even if I deselect that under Prefs->Displays->Colors.

The Folder Pane isn't striped on my system (W10), so check for add-ons that might cause this. ReminderFox is known to affect the display of some elements.

The text and background colors for plain text mail are set in Edit/Preferences/Display/Formatting/Fonts & Colors/Colors.

My Add-ons: Lightning, Enigmail, FileLink, LookOut, Provider for Google Calendar, and gContactSync I do not use ReminderFox.

I disabled them all now, but still the stripes.

Since it works in Windows, all I can suggest is that the stripes are caused by the Linux desktop theme interfering with the display in TB.

You really dare to tell someone that has been working with *nix systems for 35 years that the behavior of an application on Windows would or should be the ultima ratio for all other OS  ?!?

It's not a "desktop theming issue" ! I started my X without any window manager and without any compositor at all => no theming active at all. The behavior is the same.

--- How to replicate:

• Download debian-10.4.0-amd64-netinst.iso
• Text-Install (not graphical install!) it in Virtualbox,

 username tbtest 
 deselect "debian desktop environment"
 deselect "printer server"
 do NOT select any window managers!

• Reboot
• Login as root
• $ apt install xorg xterm thunderbird
• $ exit
• Login as tbtest
• $ echo xterm > $HOME/.xinitrc
• $ startx

 Start thunderbird in the now opened xterm:
 and configure an account, then quit (Ctrl-Q)

• setup the chrome profile directory as you suggested
• start thunderbird again

Again, this is plain X, no theming at all, still stripes!

Thus, I guess, this is a bug in TB.

In Thunderbird, what is the name of the theme you have currently set as default?

Is it Thunderbird's 'Light' or 'Dark' theme or is it 'Default' - a theme with the operating system colour scheme?

Try adding:

  /* remove zebra striping */
   #folderTree treechildren::-moz-tree-row(odd) {
       background-color: transparent !important;
   }

I would appreciate some feedback on what you receive in the email. Recently, part of the code was being removed in the emails sent when comments were posted. EG: after the word transparent there should be !important; . It would be helpful to know if they have corrected the problem and you do see the code correctly. Note: it is shown correctly in the forum.

@toad-hall A1: I have a dark theme on my desktop, while the shown debian-basic-netinstall does not have any desktop-theme at all. Thunderbird uses the "default" theme in both cases. Both instances show striping.

A2: If I receive an email, then I go to the website and read what anyone has written here. I did not copy anything from the mails.

Having started my TB with your addon (additionally to the lines that were already there), it did the job for 2 of the 3 panes (no stripes). The third one (content view) is not changed. If I open my address book then, I find the left pane unchanged, and the right pane striped.

I can use this setting to set odd lines with colours, so the following should remove the zebra stripes from the address book list of contacts.

/* remove address book contacts list zebra striping */
#abResultsTree treechildren::-moz-tree-row(odd){
background-color: transparent !important;
}

Just for the record; When you downloaded thunderbird to work on debian, did you get a download from the official page as shown below or from another source?

• https://www.thunderbird.net/en-US/thunderbird/all/

\*nix users usually get their thunderbirds from their respective repository not from a given link.

The debian netinstall was just an example. I installed it like that in order to show that the error occurs even with the smallest X install without any theming. That installation can be setup in less than 10 minutes, provided you have Virtualbox or any other virtualization software at hand.

Btw, I do not use Debian directly. I use Mint and Arch.

Your last comment about the address book worked, still some panes missing. Is there a list of all the targets that can be handled like that (kind of documentation) and is there a documentation for the WebExtension theming as well?

Yes, you are correct, I have noticed various Linux OS getting thunderbird from another source, but sometimes it has thrown up some issues that were resolved when they downloaded from the official webpage.

In your case, something in OS is overriding. Similar display issues were found with other OS eg: Windows 10 which has a default app setting for themes independent of default theme for desktop.

It might be worth uninstalling just the Thunderbird installation (not the profile) and then downloading a fresh copy from the link selecting the linux download.

Seriously?

As of the basic netinstall: The Debian package has all dependencies inside. That means it pulls all required libraries automatically, while your link just gives me something, where I have to add libraries manually on my own. As mentioned: You can setup this system in 10 minutes, and add the dependent libraries on your own. It's unlikely that anything will change in that behaviour.

On my Mint system: The stripes are still there with that version. No change in behaviour.

By the way: Why does that Version 68.10 make a new profile ?? Are all users supposed to re-configure all their accounts and add-ons when their distribution switches to that version?

re : Seriously?

I would not suggest it if it had not worked for others. Sometimes using a download from an official download webpage for a product works.

re:Why does that Version 68.10 make a new profile ?

Since version 68, there was a change in profile management designed to faciliate those users who are using more than one installation version of Thunderbird. So each version of thunderbird could operate on a different profile. This has caused a certain amount of headache for some users whilst they get things sorted out again, but in general it works ok.

If you upgrade, it should use the preset default profile, but if it does not and ends up creating a new default profile and insisting on creating a new account, then it should still be possible to reselect the original profile via 'Help' > 'Troubleshooting' - click on 'about:profile'. However, if you perhaps were using a beta and now want to use a daily release, you would in effect be downgrading and it may not pick up the profile; there is a workaround to force this. Good info at this link. https://www.thunderbird.net/en-US/thunderbird/68.0/releasenotes/?source=techstories.org