This is likely a problem with your userChrome.css file in case you use this file to style the user interface and you need to check whether there is an update available.

More info about userChrome.css/userContent.css in case you are not familiar: *https://www.userchrome.org/what-is-userchrome-css.html

I don't understand. I haven't touched my userChrome.css file (which I set up with great difficulty plus some help from this site a few years ago solely to reduce the spacing between Bookmarks after Firefox started wide spacing).

So why and how would an unchanged userChrome.css file suddenly have a problem that would move my tabs from below the navigation bar to the bottom of the screen?

More to my point, how the heck do I get tabs back to the top where I can see them (right now, the left-most tab is hardly readable because a bookmark shows through, and the plus sign to add a tab has vanished entirely). I assume Firefox changed something with 108.0, but I'm helpless in trying to figure out what to do.

Added comment: Searching through Google I see many other Firefox users are having problems with missing or moved tabs and other screen elements under 108.

So: Please, Firefox, fix the problems in 108, or provide us all with advice for lay folks on how to get out screens back to where they were.

Customization done via userChrome.css/userContent.css isn't officially supported, so using this is at your own risk especially if you do not have the skills to fix the code if it breaks or otherwise no longer works properly.

You can try to ask advice at the Firefox CSS subreddit forum.

• https://www.reddit.com/r/FirefoxCSS/

WARNING: modifications made through a userChrome.css or userContent.css file can stop working as Firefox evolves in new releases, and can break Firefox or cause strange behavior.

This is why those of us who lack coding skills but appreciate much about Firefox (I'm still here for the bookmarks sidebar, frankly) get so very frustrated -- something changes and we don't know why, something breaks and we don't know how to fix it, or some feature or option vanishes and we don't know where or how to get it back.

Anyhow, cor-el, thanks for your attention and advice.

Hi K, most likely you leaned heavily on rules from someone who posted them online. You can go back to the source and most likely get an update, or find out from the other tinkerers on r/FirefoxCSS where a new working set of rules is.

https://www.reddit.com/r/FirefoxCSS/

If you only have a few lines of CSS code in userChrome.css then you can post them in a reply and we can have a look, but if you have tens of lines then this is not workable and you are better of with the Firefox CSS subreddit forum posted above by both of us.