Greasy Fork

Only partially fixes Visited in Firefox 43.0.2

With this script installed visited links now change color--but not the color I chose. The color picker provided with Visited is useless.

In Visited.
Try clear your Site Exceptions in Visited config.
Sample: http://i.imgur.com/joWUBLD.png

If you want to use Site Exceptions. You need to edit Visited Lite after install it.

I had cleared the site exceptions first.
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Subsequent to my post (above) for the first time ever in many years, Firefox would not load, so I loaded it in its Safe Mode, and removed GreaseMonkey. Now both Firefox and Visited work fine.