I think this is considered a bug, even if just a minor cosmetic one.
Thanks for the category correction @falco. I never can figure out when something like this should go in bug or ux.
- Go to a topic.
- Change your watching status.
After clicking away, the border that usually only shows when the “dropdown” is shown remains.
This also happens in a second place.
- In a reply, select the gear.
- Choose “Hide Details”.