I notice with the release of FF57 and the square corners that there is no help on how to bring back the rounded corners of previous FF versions? Was this something the Mozilla org tried to avoid helping users whom got updated or choose to update but wasn't given options here? I found a sites that with the use of chrome.css brought back the rounded corners and gave back more control and on another forum how to switch legacy option back on for older Addons if they still worked.