You can't delete system fields - but you can hide them so they don't show up in dialog boxes where you select fields. You have to untick the checkbox called "Show System Fields" in the same dialog box that you had in your screenshot.
You can't delete system fields - but you can hide them so they don't show up in dialog boxes where you select fields. You have to untick the checkbox called "Show System Fields" in the same dialog box that you had in your screenshot.
