Will Mozilla Firefox get back into the race with its new test pilot features?

Mozilla Firefox have been testing their new features and this week they've launched 2 new features.

Fire fox color extension feature, which allows us to customize the theme of our browser as preferred.

Side view ; It allows us to open another browsing tab into the same tab within the same browser window.But it seems similar to the snap feature of windows.

Have you tried any of these features? Which one did you like the most?