Sketcher > Constraining Geometry > To Control the Display of Constraints
  
To Control the Display of Constraints
Contraints are displayed in Sketcher by default. To toggle their display, perform the following operations:
Set the sketcher_disp_constraints configuration option.
Click or clear the Show constraints check box in the Sketcher area of the Creo Parametric Options dialog box.
Toggle the Disp Constr button in the Sketcher Display Filters on the Graphics toolbar.
Click View > Display > Disp Constr.