There are a couple of cons here: you can't simply drag an open tab over to the Side View button or the sidebar, and the second tab does not have its own address bar. You can access bookmarks from the sidebar, but clicking one opens that page in the main tab. So, it's not completely intuitive, but Side View is still a neat little feature.

The second new experiment is Color. You can use it to tweak the colors and textures of pretty much every part of the browser window to create your own theme. You can share your new look (each theme gets its own URL), while Firefox created a few themes to inspire your own creations.

While both tests are fun, there's no guarantee they'll make it to a full Firefox update. Mozilla has added some other practical features recently, like limiting how Facebook tracks your web activity and blocking annoying push notification requests from sites. It's good to see Firefox focusing on form as well as function with its latest experiments.