I've got a new Mac Pro to replace my 2011 iMac workstation. I'm getting a Cinema Display, but it won't be here until tomorrow. Unable to resist, I plugged the thunderbolt cable into the iMac. The display takes over when I press Command F2, but I only see a gray screen with a radial gradient that's lighter in the center of the screen. There's a mouse cursor in the upper left hand corner, but since I haven't paired my bluetooth keyboard or trackpad with it yet, I can't get it to respond. Is this normal? And if not, what would be my next step to troubleshoot?