Back to 5*. Tried it on a few pages and it seems to be working. Thanks. Original Review: It worked great when I first installed it but then the icon didn't activate it anymore. Even online reads that were just text no longer turned black. Tried having it always on. Then the problem became it darkened white on black text to black and that seemed to be unaffected by the slider setting. After days of trying various things I uninstalled and plan to re-install. Hope it wasn't update that caused the problem. If it was I'll disable and watch for next update because I really 5* liked this when it worked. Thanks for developing this to help those of us who detest grey text and a bigger thanks on behalf of those who are vision impaired.