I have a several stacks of 30 or so tabs that I open to run though logs every morning. I had the classic theme restorer on firefox before to add the static close tab button on the right side of the tab bar so I could quickly close the tabs as I review each screen. This had the benefit that if I had to move the pointer to scroll down the page, I did not have to hunt for the new close tab position as the tabs resize themselves as the close tab button never moved. With Firefox 57 I have to hunt for the close tab button now as if I have to move off of the tab close button to scroll, they resize and move. I also have a problem with the tabs moving after closing 3 or 4 tabs so I have to reposition the pointer back to the current tab close button.