This is just so good.

Really enjoying this add-on! My one major gripe though is that the "Always Open This Site in..." feature does not always work. If I want a website such as LiveJournal or Tumblr to always open in a certain container, this feature will only work for the main site page. It will not work with anyone's blog, because the url, is [blogname].[mainsite].com. For example, if I have tumblr set to always open in container X, tumblr.com will open in X, but staff.tumblr.com will not.

Horrible for google accounts.

Single greatest add-on in the modern browser era

Please add an option to stay de-contained!

Also the UI needs improvement... especially for fast switching of containers.