Also it is possible to open up the internal HTTP server to everyone (it will bind to 0.0.0.0 address). In that case you will need to set a password to protect proxy switcher from being used in uncontrolled fashion.
In recent versions it is possible to bind specific proxy server to dedicated internal proxy server
running on a specific local port. Right click on any server and pick "Bind Proxy Server to local port" and pick
appropriate sub menu item.
After which internal proxy server will be started. Port number is shown in the log.
Server will be bound to address 127.0.0.1 .

Internal Servers Dialog
Starting from version 5.7.0 a dialog (View->Internal Proxy Servers...) has been added. There you can view the currently
active internal proxy servers and their optional targets. Also it is possible to re-bind them to different ports. At this moment
if you rebind the default internal proxy servers (ports 3128 and 1080, or others set in preferences) the changes will not be saved
over the restart of the program.