Nikon D800 issue solved

Nikon D800 causing problem until I found out the answer, so beware.

What happens is if you assign the shutter button for videos in the setup menu it greys out lock up mirror for cleaning and dust off ref as well. This is if you assign "g4" in the movie menu to record movies as well. I thought I had lost part of the camera menu until I found the answer. it is on page 324 in the users manual under "Record movies" block. It may well effect other functions as well so worth checking out. there was something about assigning to another memory bank such a "D" for example but I could not be bothered to go into all that.

link
https://www.dpreview.com/forums/post/50300280

this doesn't happen on the nikon D810 I should add