Not op, but the way i see it option 2 is the best one.Like, when you create a webapp, it asks you the website and what container it should be in.The webapp then always opens in that container, two webapps from the same site but different containers a...
the only useful thing i can think of Firefox doing is showing price history, other than that id prefer that things like coupon hunting to stay on extensions
the feature looks awesome so far, i don't really have any feedback for the vertical tabs that haven't already been mentioned, but for the sidebar itself, id like to see is the possibility to put any button on the sidebar (the way you currently can wi...