This modification allows to show line gaps by set the new property "Hide" of "PointPair" class an the property "isShowHide" of "CurveItem" class.
modify:
CurveItem.cs -> bool isShowHide {get;set;}
Line.cs -> DrawCurve(), DrawCurveOriginal()
PointPair.cs -> bool Hide;
Symbol.cs -> Draw()
all modified files you need