Update! Rated 4 out of 5 stars

I can confirm this, the about dialog always become white after firefox update

This review is for a previous version of the add-on (5.5).  This user has other reviews of this add-on.

It s normal

It s normal, because I need to wait every time the official release of the latest Firefox before fixing this. I won t explain in details why, but I can tell you in few words that s because the about dialogue is different for Aurora and Nightly and I need to upgrade every time something in the "chrome.manifest" file that is inside the package so the about dialogue could look ok with latest Firefox, Aurora and Nightly.

5.6 version solves it. You can already download it here > https://addons.mozilla.org/en-US/firefox/addon/ft-deepdark/versions/