If the proxy-server security is breached then a hacker could modify the proxy to exploit the browser bug, even if the proxy does not normally use persistent connections. Not using persistent connections is a big performance penalty, especially on slow connections like modems. Workaround 3 does only hide the problem. It does not workaround the actual problem, only the end-user visible effect of it. If you see a lot of garbage above, then it isn't.
Press reload to retry the test.