The Design Module enables on/off properties for constraining the other properties of 2D geometric primitive and operation commands. The property name is obtained by appending constr to available property names. The default is on in operation features and usually off in primitive features. A constrained property cannot be modified by constraint and dimension commands. Properties that do not have a constr property are always constrained. With the Design Module some features also have properties for controlling a corresponding symbol in the Graphics window.