Strange behavior of Highchart tool tip - hover

Question

The tooltip in my Highchart is behaving strangely. It is living its own life. It doesn't show the tooltip of the point on which I hover, but shows the tooltip of any point randomly.
Here is a JSFiddle example: http://jsfiddle.net/AeV7h/9/
$(function () {
var data=[[28,0],[24,3],[16,10]];
var param= { WodTag: "cur_spd", Name: "Current speed", Color: "#C6C6C6", LineStyle: "Solid", SeriesType: "line", LineWidth: 2, TickInterval: null, MinValue: null, MaxValue: null, Decimals: 2 };
$('#container').highcharts({
chart: {
height: 700,
width: 400,
plotBorderWidth: 1,
plotBorderColor: '#E4E4E4',
},
xAxis: {
title: {
useHTML: true,
text: param.Name + "( m/s )",
},
gridLineWidth: 1,
min: param.MinValue,
max: param.MaxValue,
gridLineDashStyle: 'Dot',
tickInterval: param.TickInterval
},
yAxis: {
title: {
text: 'Depth(m)',
},
reversed: true,
tickLength: 50,
gridLineDashStyle: 'Dot'
},
title: {
text: null,
},
legend: {
enabled: false
},
credits: {
enabled: false
},
tooltip: {
useHTML: true,
formatter: function () {
return this.y;
}
},
series: [{
name: param.Name,
data: data,
color: param.Color,
dashStyle: param.LineStyle,
lineWidth: param.LineWidth,
type: "line"
}]
});
});
Can anyone help and tell me why it is behaving like this, and how I can fix it?

Answer 1

Your problem is that your data is not sorted by increasing X value. If you read the Series.data documentation it says that (API):
Note data must be sorted by X in order for the tooltip positioning and data grouping to work.
You should always sort your data like this before handing it over to Highcharts. Highcharts doesn't sort any data. Doing it by hand for your example your data should look like this:
var data=[[16,10],[24,3],[28,0]];
As in this JSFiddle demonstration, and everything works as intended.