Right now, proxy injection (PI) mode needs to be configured from the command line, and takes over the entire Selenium proxy for a single session. We should run each PI session on a separate port, so we could configure multiple proxies on the same machine to support multiple sessions. (... not that this will work for IE or Safari proxies, which just use the system proxy anyway.) This would eliminate the need to configure proxy injection mode from the command line, which would make Selenium RC easier to configure on the client side: you could choose to launch any particular session in PI mode just by passing in a browser option.