57.0.2 on Windows, first install: None of the settings has any effect, after restart, in safe-mode, you name it; I've spent almost half an hour of my life messing around on about:config, trying out the combinations, just hoping to get this add-on making *any* difference at all. Result, flat zero. I wouldn't even know it's properly installed were it not for its entry in the Options menu, apparently the only thing it managed to do on my setup. No idea why this is featured, sorry. Less so since there was an update, as it seems, only a month ago. Did FF even change in a relative way, as recent as that? And then no note about possible problems, a month later? I'm removing.