Working with my laptop both at work and at home i walk into proxy settings every time
this is now solved by setting the proxy after i login and using a 'apply sysyemwide' and typing the password twice.
As you can image this is annoying.
The most care-free solution for me would be for the system to see which ip adres was assigned and set the proxy settings to match
For this i made a request, see:
proxy-settings-in-network-manager