Canon EOS-1D X Mark III EOS-1DX Mark III Advanced User Guide - Page 94

Dimmed Menu Items Example: When Highlight tone priority has been set Dimmed menu items cannot be set. The menu item is dimmed if another function setting is overriding it. You can see the overriding function by selecting the dimmed menu item and pressing < >. If you cancel the overriding function's setting, the dimmed menu item will become settable. Caution You may not be able to see the overriding function for certain dimmed menu items. Note In [ : Reset camera], you can reset menu functions to the default settings by selecting [Basic settings] in [Reset individual settings] ( ). 94