Very useful add-on. One of the reasons I switched back to Firefox as I heavily use multiple accounts for one cloud based service and this allows me to log in as the different profiles without having to open new browser windows. What would be very handy though is to be able to include the icons in the tabs as well as the colours to make it easier to identify which tab is doing what and also to be able to arrange the order in the container drop down so I can group appropriate container types together when selecting opening a new container.