Running Windows 7 Build 7067 x86 on a Dell Latitude D820 with an NVIDIA Quadro NVS 1200 video card.  If I let the system sleep or hibernate when connected to the docking station and then wake or resume not connected, GUI is not in Aero mode upon wake/resume.  This behavior is the same if I let the system sleep or hibernate when disconnected from the docking station and then wake/resume when connected.  Behavior is also consistent whether using the MS NVIDIA Driver that comes with Win 7 or the Dell Vista video driver.  Logging out and logging back in returns the GUI to Aero mode.