Default Firefox theme? Default Windows 10 theme?

Thanks for your quick response Sorry for my slow one.

Not sure what you are asking about. If you mean the background and colors for the window, it is the same as I had before. It is called Walnut2 for Firefox.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Before going to Safe Mode, i switched back to Firefox Default theme and now the buttons are restored.

Thanks

You're welcome

Ok, but why is it broken when using everybody else's themes?

It's also not just since Windows 10, but any version after 39.0.