I am starting a desktop Prism project that will that has basically two UI structures that will require two different region setups.  One is for "before login", and the other is, of course, for "after login".  Would it be better to use two widows or two pages hosted within a main window?

Hi,

In my opinion, this decision will mostly depend on your personal preferences and the requirements of your scenario. Regarding the differences between WPF Pages and WPF Windows, I believe you could find the following thread interesting:

• WPF Page vs WPF Window

Additionally, I believe you could also check the following thread which contains a small sample of a login scenario using two different windows, using the RegionPopupBehavior included with the Stocktrader Reference Implementation:

• Login dialog in PRISM + WPF

I hope you find this handy,

Agustin Adami
http://blogs.southworks.net/aadami