Editor GUI; draw dotted lines using Handles

DrawDottedLines.cs

// Somewhere in your OnSceneGUI() ...

// Draw dotted lines.
var handlesColorBkp = Handles.color;
Handles.color = new Color(0f, 0f, 0.5f);
for (int i = 0; i < points.Length - 1; i++)
{
	Handles.DrawDottedLine(points[i], points[i + 1], DOTTED_LINE_SIZE);
}

Handles.color = handlesColorBkp;

// Draw drag gizmos.
for (int i = 0; i < points.Length; ++i)
{
	using (var check = new EditorGUI.ChangeCheckScope())
	{
		var handleSize = line.Thickness * POSITION_HANDLE_SIZE_MULTIPLIER;
		var handleSnap = Vector3.one * 0.5f;
		var pos = Handles.FreeMoveHandle(points[i], Quaternion.identity, handleSize, handleSnap,
			Handles.SphereHandleCap);
		pos.z = 0;

		// Record undo state.
		if (check.changed)
		{
			Undo.RecordObject(line, "Dragged Line Point");
			line.Points[i] = pos;

			var graphic = line.GetComponent<Graphic>();
			graphic.SetVerticesDirty();
			Repaint();
		}
	}
}