firefoxPref network.http.max-connections-per-server 2

[linuxfan]

I want to limit the amount of connections to the server by setting the network.http.max-connections-per-server option, but it seems to have no effect on the result. See for example http://www.webpagetest.org/result/150306_YA_J0H/ The connection graph shows that there are still 6 connections per hostname.