I was curious why my windows were all immediately getting maximized on my new kinda-netbook Dell Mini 12, running UNR (with the "Classic Desktop" mode). It's the sort of behavior you can imagine wanting -- with a small screen, maybe you do want to maximize everything? But I wanted to turn it off.
This thread has the answer!
UNR comes with a program called "Maximus", which was in my Startup Applications. To make the behavior go away, just go to System > Preferences > Startup Applications and remove Maximus from that list. Problem solved!
Seems odd that this is a process running in the background, instead of, say, a window manager setting.