I also made my own tweaks https://kevincox.ca/2021/06/03/firefox-proton-tweaks/ https://kevincox.ca/2021/06/03/firefox-proton-tweaks/ - I changed the "button"

I also made my own tweaks https://kevincox.ca/2021/06/03/firefox-proton-tweaks/ https://kevincox.ca/2021/06/03/firefox-proton-tweaks/ - I changed the "button" to be a simple rectangle the entire height of the tab-bar. - I removed extra space between the pinned tabs and the regular tabs.