What do you normally display at the top of Firefox?

• Tabs
• Title bar
• Menu bar

You could try turning some of those extra bars on/off to see whether that helps Firefox correct the display. You can do that using the Customize tab: Customize Firefox controls, buttons and toolbars.

Make sure you run Firefox in desktop mode and not in tablet mode.

• https://www.top-password.com/blog/windows-10-switch-between-tablet-mode-and-desktop-mode/

This only happened when I updated Firefox to 9.0, the icons are there, however they are not visible. I currently have to align another program (like Excel) to find the position of the icons, this is time consuming and annoying.

sorry I use the Menu bar.

Does it make any difference if you change the color scheme using a different theme? For example, this one is similar to the Firefox 57-88 "Default" theme:

https://addons.mozilla.org/firefox/addon/photon-colors/

To change themes if that doesn't help, see: Built-in themes in Firefox - alternative to complete themes.

I did not consider that the theme would be a problem I disabled the theme and the icons appear. I then enable some other animated themes and the icons disappeared. If I use non animated themes the icons appear.

I have been using the same animated theme for years; previously update Firefox with no issues. For some reason 9.0 are having issues with some of the animated themes. I was using ‘A N I M A T E D KITTY CAT (disabled)’. It appears that all the animated themes cause this problem.

Thank you very much for the suggestion, I would rather go without animated themes for the time being.

Thank you for testing that. Maybe the theme authors will need to update their themes for Firefox 90; not sure.