In addition, clicking the extension's button causes the PAC (Proxy Auto Configuration) file to be reloaded, if current mode is "Automatic proxy configuration".
Please, note: This extension only switches between proxy configurations present in the browser network settings. It is not intended to switch between different configurations specified in the extension itself. There are enough extensions for this task, whereas the main purpose of this one — a button for quick PAC file reloading. Everything over this is a "free bonus" to this button.
The home page of Proxy Mode Switcher is http://yup.lh1.in/AddOns/ProxyModeSwitcher
Also it should be available soon at https://addons.palemoon.org/addon/proxymodeswitcher/