Rated 5 out of 5 stars

Xubuntu 15.04
Thunderbird 38.2.0
MRC Compose 1.8.2
Conflict with add-on Subject Manager 0.4.2 https://addons.mozilla.org/ru/thunderbird/addon/subject-manager/
When I try to create message - Thunderbird freeze and I see gray window without any symbols.
***
Update: Xubuntu 15.10, Thunderbird 38.4.0, MRC Compose 1.8.2, Subject Manager 0.4.3 - everything OK :)

This review is for a previous version of the add-on (1.8.2). 

Hi,
I just tested and had to no problems (I installed Subject Manager *after* mrc compose).
Please use support email if you have further details about your problem.
Cheers, Michel