highslide-software/highcharts.com — comment on commit fd67dea0fbca3a190ce0097f7ae8b6b86cf302fe
File:  line 0
By HoangNV:

This fix causes the tooltip cannot be shown when there's a series with data=[]. Please see this example: http://jsfiddle.net/boykocodon/Tawpb/12/