
The All-in-One Sidebar Firefox extension squeezes a whole slew of extra features into your sidebar, as the website explains:
“All-in-One Sidebar (AiOS)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. You can set the orientation to left or right, set the minimum, default and maximum width and the behavior on browser startup.”
I like the option to load pages in the sidebar, it’s great for comparing two web pages and the extension does not slow down Firefox as much as the split browser extension does. Also there’s a ton of keyboard shortcuts to play with.
All-in-One Sidebar is free and works wherever Firefox and flock do.
All-in-One Sidebar website
All-in-One Sidebar Extension