Lightning 1.5.2 Rated 5 out of 5 stars

You can D/L Lightning 1.5.2 here:
https://addons.mozilla.org/en-US/thunderbird/addon/lightning/versions/?page=1#version-1.5.2

This review is for a previous version of the add-on (1.5.1).  This user has other reviews of this add-on.