GoToolCreating ctool = new GoToolCreating(goView1);
GoPolygon tri = new GoPolygon();
tri.BrushColor = Color.LightBlue;
tri.AddPoint(5, 0);
tri.AddPoint(0, 10);
tri.AddPoint(10, 10);
ctool.Prototype = tri;
goView1.ReplaceMouseTool(typeof(GoToolRubberBanding), ctool);
GoToolCreating ctool = new GoToolCreating(goView1);
GoPolygon tri = new GoPolygon();
tri.BrushColor = Color.LightBlue;
tri.AddPoint(5, 0);
tri.AddPoint(0, 10);
tri.AddPoint(10, 10);
ctool.Prototype = tri;
ctool.Modal = true;
ctool.OneShot = false;
goView1.Tool = ctool;