Nikon Flash Blacks Out Screen

[Lenbabin]

Trying to solve a mystery.  My Nikon SB 700 blacks out the rear screen (and the viewfinder) when I slide it onto the camera in TTL mode.  If I use manual flash mode, the screen stays lit and shows the scene according to the light the lens is letting in.  Camera is in P mode.  WB is in flash mode but does the same in Auto.  Any ideas?

thanx

Len

[JCM-Photos]

There is really no problem with the X1D and 907X removing and mounting lenses with powered on cameras, I've done it thousands of times with X and H lenses, without trouble.

Flashes and the X1D is another question (907X doesn't have a Nikon flash system) because it is only a partial Nikon System (no CLS functions), so even Nikon branded flashes are only partially compatible, and I guess that broad functional testing could not be done.
That's also why Profoto company refuses any TTL functional warranty on the X1D even when Hasselblad gives a list of TTL compatible Profoto gear.
With all these restrictions, Mounting and removing flash only powered off is a wise recommandation, even if it works fine on Nikon cameras.