Older version 3.15.3.1 is stable with Firefox 53.0 and icon displays "D" functionality correctly. Icon reverts to generic green blob and functionality disappears with most current 5.18.21 update (Firefox 53.0, WIndows 7).
Thank you for sharing what you're seeing with our most recent version of our extension. We have had scattered reports of users having trouble with it, like you're describing, and our team is continuing to investigate what is causing this unwanted issue for these users.
