Overlapping address bar and tabs in Firefox 56 for Mac OSX. What to do?
The last Firefox update left us with the address bar overlapping the tab bar.
What can be done to fix this very annoying issue in Firefox 56 on Mac OSX (El Capitan)?
Alla svar (1)
Your Tab Groups 2.1.4 extension is the culprit - when you disable it, everything will be back to normal.
Read the first sentence under 'About this add-on': https://addons.mozilla.org/en-US/firefox/addon/tab-groups-panorama/
As an alternative you could consider 'Tab Groups Helper', although at this point it's not 100% certain if this add-on will be ported to Webextensions' : https://addons.mozilla.org/en-US/firefox/addon/tab-groups-helper/