Mark close notification more clearly

Problem: The close status change as seen here:

is not distinguishable from other events.

Benefits: While here:

you can see in an instant when the issue was closed.

Goals: decrease the visual scan time needed to understand the history of an issue.

Use distinct icons for the different events, and a red one for the close status event.

Edited May 23, 2019 by Iulian Onofrei