Today I found a solution from https://forums.linuxmint.com/viewtopic.php?t=331078 The key is to modi

Today I found a solution from https://forums.linuxmint.com/viewtopic.php?t=331078 The key is to modify or add a line in

"/home/user/.mozilla/firefox/"your name profil"/prefs.js

Open file "prefs.js" with text editor. Change browser.tabs.drawInTitlebar true to false or add the line if it is not there.

Cheers, xgiannak