The tab sidebar extension, if you haven’t heard of it already, provides a sidebar in the browser that can act as a replacement to the main tab bar, complete with always visible preview thumbnails and in tab navigation buttons.
Since Tab Sidebar provides a replacement for the main tab bar, when the sidebar is visible Firefox’s main tab bar will be hidden. If you still wish to use the main tab bar then you can show it again from the Tab Sidebar options. {via ghacks.net}
Add to Firefox
