This is a post in Firefox Extensions

All-in-One Sidebar - a sidebar extension for Mozilla Firefox!

Te All-in-One Sidebar is a sidebar control, inspired by Opera’s. Click on the left edge of your browser window to open the sidebar and get easy access to all your panels. It lets you quickly switch between sidebar panels, view dialog windows such as downloads, extensions, and more in the sidebar, or view source or websites in the sidebar. It includes a slide-out button and a toolbar, all of which can be extensively customized.