Rated 4 out of 5 stars

This add-on is very helpful, but there is a troubling problem.
If I restart Thunderbird twice after activating this add-on, the Star and Read/Unread icon becomes invisible.
It works fine on restarting just after activation, but when I restart again, it occurs.

Environment:
TB 68.9.0 (64bit*)
* The same problem occurred in the 32bit version.