Calling QLegend::setMarkerShape() with argument QLegend::MarkerShapeFromSeries causes a crash

Steps to reproduce:

• Run the sample application attached.
• Press "Run Test Sequence 1: Default Marker Shape" button -> works
• Press "Run Test Sequence 2: Marker Shape From Series" button
  EXPECTED: The shapes of the legend markers are selected according to the series in the chart and the markers are updated successfully.
  ACTUAL: The application crashes.