Please .. Nikon .. Before you send the D400 off to production make sure to re design the rubber door that now is on the the left side of the D300.
It's great if you don't use it but after some use it is impossible to keep closed. After almost ten days in Maui I spent way too much time trying in vane to keep the flap closed on an otherwise flawless D300.
Has anyone else contended with thiss problem ? It's driving me nuts !!