Use this editor if you wish to create/edit an achromatic mark that is saved as a resource in "Marks". For that reason, only register marks, plate control marks, scavenger marks and Klebrand code marks display as a "mark type". Use the editor for control control bars (page 343) or ink pickup bars (page 340) if you wish to create color marks.
See also the description in the "Editors for Marks, Color Control Bars and Ink Pickup Bars" section.