It used to have a small color tab in the folder pane on the left hand side. Indicating that the folder was selected.

This ismall "color tab" is not the default to mark a selected folder in the folder pane. Maybe you used an add-on which is no longer compatible with actual Thunderbird versions. By default a selected folder in the folder pane is distinguished from other (non selected) folders by background color which depends on whether the selected folder is in focus or not. Exemple: in my picture th Sent folder is selected and not in focus

Thanks mapenzi that is interesting and useful. 'l'll have a look at my extensions. That coloured icon isn't very noticeable. It would be better to have a more eye catching indication.

Thanks mapenzi that is interesting and useful. 'l'll have a look at my extensions. That coloured icon isn't very noticeable. It would be better to have a more eye catching indication.

You can manually choose whatever colour you prefer to see. A bit laborious but once set up it's fixed until you change it. Suggestion - if you have more than one account - change colour for eg: Junk/Spam and then do all the various Junk/Spam so you have same colour, then do another batch.

The icon used for the account name - The colour of that icon can be set in 'Account Settings'

• Select 'Account Settings'
• Select name of account in left pane and on the right side near the top is a 'Colour' option
• click on it to open a small window offering colour options.
• select a prefered colour and click on 'OK'

For any other folder in Folder Pane

• Right click on folder and select 'Properties'
• It offers you a 'Colour' button
• click on it to open a small window offereing colour options.
• select a prefered colour and click on 'OK'

If you are wanting to set eg: all the Junk to a strong red

• Right click on Junk/Spam folder and select properties
• click on the colour option
• select a stronger red
• click on the add to custom (assuming it's not one of the default selection)
• then click on OK

You can work through your various accounts setting up the same colour on each 'Junk/Spam' folder. It saves you from trying to remember exactly what you selected.

That coloured icon isn't very noticeable. It would be better to have a more eye catching indication.

hello, you misunderstood my first screenshot above. It's from my working profile where I put some colors by means of a userChrome.css file. It wasn't the color of the icon of the Sent folder but on the background color of the entire selected Sent container I wanted to draw your attention!

That's why I want to show you two new screenshots taken in the Thunderbird main window such as it looks by default on a Mac:

• the first image shows a selected Inbox folder in my folder pane. It also is in focus and that's why its background color is light blue which is the highlight color for a selected/focused folder.

• the second image shows a screenshot taken when the same Inbox folder is no longer in focus because in the meantime I clicked the message pane with the pointer of my mouse. You see that the background color hast changed from light blue to light gray but one can still easily distinguish the selected folder from other non selected folders.

So I still wonder what you are looking for to distinguish selected and non-selected folders in the folder pane:::

That explains it nicely. Thanks for clarifying.