Do I stay logged into WM if I launch another application on the iPhone?
No, this is a current limitation of the iPhone. Apple does not permit other applications to remain active in the background. You will need to restart WM after launching a different application. If you receive a phone call while using WM, you will need to restart WM. Restarting WM takes only a few seconds. You will not lose any data that has been saved up to that point.