No. That's just the nature of the Mac version.
Your last workspace set-up returns automatically on the Windows version.
Not on my windows version win7 64?
On my version PRE10 on W7 64 bit it does. Important is that the second monitor is on before you started the program. Just as Steve says every time the program returnes to the latest arranged screens.
Thanks everyone for your interest. As I mentioned, I'm using an iMac and I guess the problem lies within the many differences between that operating system and Windows.