The background color of the Folder Pane and Threads Pane can be modified with a userChrome.css file:

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

#folderTree,
#threadTree
{
  background-color: #D3D3D3 !important;
  color: black !important;
}

1. Help/Troubleshooting Information, click Show in Finder to open the profile folder, close TB. 2. Create a new folder in the profile folder named chrome. 3. Create a text file in the chrome folder and save it as userChrome.css. 4. Copy the code posted above into the css file, Save. 5. Restart TB to see the panes with colored backgrounds.

To add colored buttons, try Phoenity Buttons.

Thanks for your reply

I have downloaded Phonety Buttons, but they do not load onto the toolbar, only show in Extensions and I have enabled them and quit and opened up Thunderbird and nothing changes.

The background colour change I have tried to go through the instructions, but the suggested way of doing it it beyond me as, nothing opens as is proposed in your instructions.

What is your version of TB? For TB 60, install Phoenity Buttons 2.7; v. 3.3 for TB 68.

https://addons.thunderbird.net/en-us/thunderbird/addon/phoenity-buttons/versions/

The attached picture shows the panes with a light grey background and Phoenity Buttons in TB 68.

The clue is in the topic header 60.9.1

I have also added through add-on an extension to remove email duplicates, which again although enabled does nothing.

If you're referring to this add-on, I don't know why it wouldn't work. Some add-ons are platform dependent, but this is usually mentioned in the description.

Yes, that's it. As, I say, it's the same with phoneity buttons, nothing happens.

Worked out now why the Phoenity Buttons would not work by contacting developer.

As far as The duplicate email function goes it's did not work because was non-specified account because I am piggy backing off Onetel as a TalkTalk customer. However I pulled out an older Thunderbird data file from TimeMachine and I have my original account back now. The remove duplicates works now, but took a lot of emails out into trash that were not duplicates which is weird as, now I have to put them all back in the correct folders. Technology eh, It takes up a lot of time.