Advanced WiFi network settings are not per-network? Like most people, I move often with my laptop, and thus I also often switch WiFis networks. There is a WiFi network I often connect to which requires the IP to be entered manually.

So I opened Network Preferences, picked WiFi, clicked Advanced..., TCP/IP, and I told it to "Configure IPv4: Manually". I entered all the info and it connected just fine.

But now I am back home, where I always get the IP using DHCP. To my surprise, the "Configure IPv4" stayed at "Manually". Why didn't it revert to DHCP?

In short, why isn't the "Configure IPv4" option per-network as it should be? What's the idea behind making it a global setting for all networks?

And finally, can I make it a per-network setting?
You can change your location in the apple button in the menubar, that way you won't have to open the system preferences, there are apps to change system preferences according to wi-fi connection: at the bottom of this post some are mentioned