Rated 4 out of 5 stars

Therer is a bug that causes high(er) cpu usage.
is the Thread that comsumes the cpu usage if the addon is installed. This Thread does also exist without the addon, but cpu usage is minimal without it.
It makes no difference if thunderbird is open, minimized or in the system tray.

This review is for a previous version of the add-on (2.4).