Comment 1 for bug 300271

When the "Apply system-wide..." button is pressed, changes are written to /etc/environment. However, this file is written incorrectly because the username/password is omitted. Also there is no no_proxy setting for the ignored hosts.

This is easy to observe. Change the gnome-network-preferences. Press "Apply system-wide". Open a terminal and

set | grep proxy; cat /etc/environment

to observe the differences.