Hi rick_hoskins, there actually are two new tab buttons:

• the button for when you only have a few tabs on the bar
• the button for when you have so many tabs that there are left and right scroll buttons on the bar

Neither of these buttons should completely disappear, but only one is visible at a time.

In the Customize panel, did you try the "Restore Defaults" button to return any removed controls back to the bar? You will have to repeat your customizations of the bar after that.

Have you set up a userChrome.css file to customize the toolbar area?

Hey, thanks for the reply. This is the "only a few" button I guess, moving across as I add tabs and latching to the right as I exceed the visible screen space. When I add so many tabs that they are tiny, then a second "add tab" button does become visible, and that one works fine / stays visible.

I did try restore defaults and it did nothing.

I haven't set up a userChrome.css file that I'm aware of but I suppose in the past that may have happened, it's been many years since I had a completely fresh install - probably 10 years. I will take a look at resetting that file, see if that will resolve the problem

Ah, well. I looked in the userChrome file, there was a bunch of stuff about tabs in it. So I renamed that, and reset. Problem solved, the + button now appears properly and is visible. New problem, the tabs have a terrible rectangle appearance which doesn't go with anything else on screen. Still, the button works so I guess, there I go, learn to live with awful design change.

Thank you :)

Hi Rick, if you decide you can't live with the boxiness, you could try one of these next:

(A) Figure out the source of the shape changing code and see if they've issued an update for Firefox 70

(B) Post your userChrome.css file on Pastebin (or another text file sharing site) and ask for help on either of these sharing a link to your paste:

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