According to your system details submitted to the forum, you are running Firefox 52.0, which has not received updated since September last year. This version also did not receive any updates to the user interface.

If you are running a version higher than Firefox 65 (which you are not if you are still on Windows XP), then this thread has the solution to putting the tabs back at the bottom of the browser.

Hope this helps.

Hi shiftF12ATweb.de, maybe you missed that there have been add-on problems in Firefox for a week now. A certificate used in most extensions expired, and every version of Firefox needs a new certificate to verify previously signed extensions.

The developers built a legacy extension that works in Firefox 52-56; that was finished nearly 48 hours ago. However, there have been problems with how it would be automatically pushed out to users through automatic updating.

As a workaround, it will be posted on the Mozilla Add-ons site (or another Mozilla site) for manual installation. That should be soon, but some sign-offs are needed, so I don't know exactly when that will happen. An update should be added to the blog post:

https://blog.mozilla.org/addons/2019/05/04/update-regarding-add-ons-in-firefox/

If you want to jump ahead and use the add-on from Wednesday now, it is attached to a "bug" tracking entry here:

https://bugzilla.mozilla.org/show_bug.cgi?id=1549604#51

Then if you are using Classic Theme Restorer or another legacy extension to change your toolbar order, it should work again.

You are right, i am using XP and version 52.9.0 and indeed, there was an update, because suddenly when there was this problem with this certifcate, my tabs went up. no update was signaled, i clicked on nothing, it just happend.

i want my tabs to be on bottom and it would be great of you guys there at firefox team, to implement a function in EVERY firefox giving the user the very easy button-choice where he or she wants to have their tabs.

i have chose a very hard way now with backups and older images restored. frustrating. i will try that solution from above

There was not an update. Unfortunately. A certificate used to sign add-ons expired. So now you need to install a new certificate. But I am repeating myself. You know what to do.

it worked out with the second link offered there. for me as a non programmer it is always tricky to find the path through those things which for you are extremly easy. so, many thanks for that help, addons now working again.

shiftF12ATweb.de said

i want my tabs to be on bottom and it would be great of you guys there at firefox team, to implement a function in EVERY firefox giving the user the very easy button-choice where he or she wants to have their tabs.

This is actually a feature that I'm sure quite a few Firefox users would like to have, since it's only possible with a CSS tweak at the moment (which can be hard for non-programmers).

Unfortunately for you, even if the Firefox developers were to add that feature in, you wouldn't be able to update to the latest version of Firefox on your current system. It's not practical to expect the Firefox developers to apply these changes to legacy versions of Firefox that are no longer supported, especially considering the number of interface changes that have been implemented on newer versions of Firefox.

If you want to leave feedback for Firefox developers, you can go to the Firefox Help menu and select Submit Feedback... or use this link. Your feedback gets collected by a team of people who read it and gather data about the most common issues.

In Firefox 52 you can use Classic Theme Restorer or use code in userChrome.css to get the tabs on bottom.

• https://legacycollector.org/firefox-addons/
• https://github.com/JustOff/ca-archive