Users confuse Torbutton/browser proxy settings with Tor Network Settings
We have reports from the helpdesk that users are confusing the Torbutton proxy settings UI (and probably the Firefox proxy settings UI too) as being the place where they need to enter proxy settings for Tor/PTs to use. Worse, when they change either the Torbutton or Firefox proxy settings, Tor Browser stops using Tor.
We should figure out some way to fix this. One approach that brade suggested was to conditionall overlay Tor Launcher's Network Settings UI pane into the Torbutton settings UI, so that users see that UI first, before (or perhaps better: instead of) the Tor proxy settings.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information