I have been spoiled by a great feature of Safari. I usually start out working with one browser window full of tabs, and then at some point decide that I need to look at two pages at once. At that point, I just drag out one of the tabs to a new window. I use Firefox as least as much as I use Safari, and it bothers me every single day that I can’t do the same thing in both browsers. And while I’m sure that this functionality can be enabled with a Firefox extension, I’m not too excited about that solution since my previous experience with tab-enhancing extensions has yielded too much unexpected behavior.
For some extra fun, hold down the Shift keywhile you perform the action.