Hi Georges, I run jessie experienced exactly the same effects since the update to 52. I have the following plugins installed: enigmail (from package) lightning (from package) google calendar provider (from package by dependancy) cardbook (from mozilla addons) inverse sogo connector (from manual download)
I checked a lot of combinations. In my case cardbook is causing the problems. I can leave all other addons activated and deactivated only cardbook. Now Thunderbird is as fast as before. Maybe it depends on combination of plugins and/or other configuration. Kind regards, Andreas
