Raising the security level of the Internet Zone (Tools -> Internet Options -> Security tab) in Internet Explorer from the default level (“Medium-high”) to “High” causes a problem for Firefox.

To block this referrer header, type about:config in the address bar, press Enter, navigate to network.http.sendRefererHeader, double-click it, and set the integer value to 0.

Internet Explorer appears to have had an ugly history but seems to be maturing and stabilizing while Firefox appears to be going through some growing pains in the last seven months. From these ...