#119 Point highlighted is not the expected point

[SimonD]

Using the followin configuration:
chart.setToolTipType(Chart2D.ToolTipType.VALUE_SNAP_TO_TRACEPOINTS);
and
trace.setPointHighlighter(new PointPainterDisc(8));

The nearst point near the mouse has is coordinate displayed properly in the tooltip but the point highlighted is actually the next point in the trace.