Comment 17 for bug 78098

Alex: The interaction with gnome-session is that gnome-session sets the env. var. according to gconf, and this setting is then inherited by all other apps in the session, see pstree:
     │ └─gnome-session─┬─Xgl
     │ ├─beagle-search───2*[{beagle-search}]
     │ ├─evolution-alarm───2*[{evolution-alarm}]
     │ ├─gnome-cups-icon
     │ ├─gnome-panel
     │ ├─nautilus
     │ ├─nm-applet
     │ ├─2*[ssh-agent]
     │ ├─update-notifier
     │ └─{gnome-session}

For example gnome-terminal sees the env. var. as overruling the gconf values, and thus stops obeying changes to the gconf settings for the duration of the session.

Gnome-session does _NOT_ set the env. var. if "use_http_proxy" is not set. The problem is that gnome-session is only able to check _once_ at startup, and this setting is then inherited and overruling.