Nikon D850 Menu Manual page 146

Option Description
If Off is selected, the multi selector is used to choose the
picture displayed during full-frame playback, highlight
thumbnails, and navigate menus. If On or On (image
review excluded) is selected, the main command dial can
be used to choose the picture displayed during full-frame
playback, move the cursor left or right during thumbnail
playback, and move the menu highlight bar up or down.
The sub-command dial is used in full-frame playback to
Menus and
skip forward or back according to the option selected for
playback
Sub-dial frame advance and in thumbnail playback to
page up or down. While menus are displayed, rotating the
sub-command dial right displays the sub-menu for the
selected option, while rotating it left displays the previous
menu. To make a selection, press 2, the center of the multi
selector, or J. Select On (image review excluded) to
prevent the command dials from being used for playback
during image review.
When On or On (image review excluded) is selected for
Sub-dial Menus and playback, the sub-command dial can be
frame rotated during full-frame playback to select a folder, to skip
forward or back 10 or 50 frames at a time, or to skip to the
advance
next or previous protected image, photo, or movie.
146 Menu Guide