Split View in Firefox: Two tabs side by side, right where you need them | The Mozilla Blog
Much of what we do on the web involves looking at more than one thing at a time – booking tickets while checking your calendar, taking notes as you go th
If you want to switch back and forth between "these two web things side-by-side" and "something else" over and over, then in that case it's better than two full browser windows side-by-side because they come into the foreground and vice versa as a unit.