This is yet another cool tool for developers which allows one to switch between the development and live server for websites and FTP. While you can simply use ALT+TAB to switch between to website tabs than use an add-on, Server Switcher allows you to have multiple development and live site pairs and places an icon on the address bar to highlight the development site.
Keybord shortcut: Ctrl+Shift+X
Open local/remote server in a new tab with middle click or CTRL+leftclick.
Support for subdirectories, different ports and local files
This add-on works fine with the Flock web browser as well.
Click here to install the Server Switcher Firefox addon.