I have two users using identical systems. Both have Dell laptops attached to docking stations and are using external mice and keyboards. If they are typing in a window, let's say a new email, and another email arrives, the window they are typing in becomes no longer active, and to continue typing they mustclick back into it. This holds true even if they are using other applications such as Word or Excel.
We have called both Dell and Microsoft tech support and they cannot figure it out. It does not seem to be related to any of the ordinary settings.