I was fond of Colorful Tabs and had donated before it was disabled by the new version of Firefox.
I found and installed the new version of Colorful Tabs. The download was allowed and it appears in Firefox Add-ons, but Firefox makes Colorful Tabs far from useful. The tab in use is the only tab that is colored. I restarted Firefox to no avail. I restarted the computer, and that didn't help either. The Colorful Tabs options can't be found either. Mo more "Send to beginning, Send to end, change tab color, etc.
What a shame.
When Colorful Tabs works it gets the highest possible ratings, but until then, zero stars.
Good luck, Shivanand. Keep up the good work!