I got a warnings trend chart in which the Y axis (number of warnings) had minimum value 42 and maximum value 43. The chart then displayed horizontal gridlines at 42, 42.2, 42.4, 42.6, 42.8, and 43 warnings. That looked a bit funny because the actual number of warnings will always be an integer. It might be good to configure yAxis.minInterval as 1 to remove those non-integer gridlines.