I am using a single monitor (IBM 2237 C71 CRT) and it does not pause when a window is maximized. Even back as far as when "Froggy" was released,May 12,2008, it did not pause as I could hear and see it running in the background. This has occured on two different rigs. One with Vista Home Basic then Ultimate,one Ultimate only.
This is mainly a FYI since it causes no problems. I seldom used DS before but that is changing. The software and dreams keep getting better and better so I find myself using it more now so I thought I would mention it.