Hi, there seems to be a bug in HighStock code. The high and low values being displayed are of a previous view. For eg, on initially when the chart is loaded in the example fiddle, it shows the values as high:0.74190 Low: 0.67380. The rangeselector button selected is 3m. Now if you select the zoom to be 1m, the high low still shows the old values while if you look from the graph, the high is 0.7024 and the low is 0.67380.
Thus the bug is that the event is fired before updating the extremes and thus reflects the old high low values from the previous range. Appreciate if someone can file a bug in the bug system for this.