Hi, I'm having trouble understanding your problem. Wdym by you want to know which tab is opened and which tab is not? They are usually on top of the browser.

Hi, Yes, at the top of the browser, but there is no difference in appearance between the more clicked and untouched tabs.

I sometimes open multiple tabs in the background by pressing Ctrl key with more than one mail on some mailer systems. then I look at these tabs by clicking on them

For an example, you can see how yandex browser works. There is a dot on the right side of the tabs that are not viewed on yandex and disappear when entering

Please examine the attached file. Thanks.

https://addons.mozilla.org/en-us/firefox/addon/tab-flag/

ok thank you solved !

https://addons.mozilla.org/en-us/firefox/addon/tab-flag/

From what I can see, this extension works with Firefox's natural behavior to display the page title on the tab. It determines which tabs have not be loaded and modifies their title in the page.

To get a dot overlaid on the title like the Yandex browser would require a type of modification that probably can't be done with an extension because it changes the appearance of the tab beyond the ways allowed for themes. There is a feature called userChrome.css which would let you make such a modification; possibly someone has already posted a style recipe for this, or can make one for you. A good place to search or ask about that is on this subreddit: r/FirefoxCSS.

More general info on userChrome.css: https://www.userchrome.org/what-is-userchrome-css.html

Thank you for helping and information