Downgraded to v19.9 and I'm happy again! :-D Rated 5 out of 5 stars
As announced before, I downgraded to v19.9. Now I got the old color picker UI back and the tab stack (thick line below the tabs) doesn't break the tab scroll function anymore. :-)))
Yeah! ColorfulTabs 19.9 gets *** 7 Stars ***! Hopefully, the author fixes the future versions and I can update again.
p.s.: I installed "ColorfulTabs fixes" stylish script -- and it's a lot of fun. Although now, I don't need it any longer to fix anything. But you can make fun stuff with the tab texts' style to make the ColorfulTabs experience even better. :-)