Wrong display with a custom scale when all values are positive

[ronenl]

I configured the options like this: $scope.chartOptions = { scaleOverride: true, scaleStartValue: -100, scaleSteps: 10, scaleStepWidth: 20 };

When the chart has mixed positive and negative values the chart looks OK, but when all the values are positive the chart looks like this:

the values are: [ { "StartDate": "/Date(1433106000000)/", "EndDate": "/Date(1433192400000)/", "StartDateFormatted": "1", "EndDateFormatted": "2", "Performance": 3.37662337662 }, { "StartDate": "/Date(1433192400000)/", "EndDate": "/Date(1433278800000)/", "StartDateFormatted": "2", "EndDateFormatted": "3", "Performance": 6.70125378297 }, { "StartDate": "/Date(1433278800000)/", "EndDate": "/Date(1433365200000)/", "StartDateFormatted": "3", "EndDateFormatted": "4", "Performance": 1.0989010989 }, { "StartDate": "/Date(1433365200000)/", "EndDate": "/Date(1433451600000)/", "StartDateFormatted": "4", "EndDateFormatted": "5", "Performance": 5.05737356566 }, { "StartDate": "/Date(1433451600000)/", "EndDate": "/Date(1433538000000)/", "StartDateFormatted": "5", "EndDateFormatted": "6", "Performance": 0.76335877863 }, { "StartDate": "/Date(1433538000000)/", "EndDate": "/Date(1433624400000)/", "StartDateFormatted": "6", "EndDateFormatted": "7", "Performance": 4.50077599586 }, { "StartDate": "/Date(1433624400000)/", "EndDate": "/Date(1433710800000)/", "StartDateFormatted": "7", "EndDateFormatted": "8", "Performance": 5.26315789474 }, { "StartDate": "/Date(1433710800000)/", "EndDate": "/Date(1433797200000)/", "StartDateFormatted": "8", "EndDateFormatted": "9", "Performance": 0.25839793282 } ]

The values are starting from the bottom of the chart instead of starting from the zero line.