This month I got more and more reports that the “Turn Off the Lights” Firefox extension (XUL version) is not working in Firefox Developer and Nightly 48.0a1 (2016-03-23). When you click on the gray lamp button the lights go not off, but in the Firefox new tab page (chrome://) it dims the page.
In the stable Firefox version 45.0.1 do you see not the issue, and works everything very well.
In Nightly I get this error in the “browser console”:
unsafe CPOW usage main.js:490
[ERROR] Error: unsafe CPOW usage forbidden
Help. How can fix this issue or is this a bug in Firefox?