Focus last-tab by double-clicking current-tab
Now obsolete, Tab Tree add-on had a useful feature that allowed the user to go back to the previously highlighted tab by double-clicking the currently focused tab in the Tree-Tabs side-bar pane. This quick usability feature is very handy when there's a lots of tabs open and for quickly navigating to the immediate last tab.
Please consider adding a feature that allows going back to immediate last tab by double-clicking (or via other means) the currently active tab. Thanks a lot.