Works in Ubuntu but not OpenSUSE. Rated 3 out of 5 stars

Have been trying to use Lightning with a single .default on all my Linux programs. Works in Ubuntu and Mint but not in OpenSUSE. The calendar outline shows grayed out. Cannot do anything with it. Can find nothing to resolve this problem.

This review is for a previous version of the add-on (2.6.4). 

Could you try (at least for testing), the stock Thunderbird from ? I suspect that there might be some issues with the distributions custom builds.