(Beta 1) Area Chart - AreaSeries SeriesItemOverEvent Issue
The tool tips for an area series do not work well.
When you add a SeriesItemOverHandler to an AreaSeries, the index and value properties in the SeriesItemOverEvent returned have nearly constant values. There is no way to determine which time interval along a TimeAxis or category item along a CategoryAxis the event corresponds to, which makes it impossible to show anything of interest in the tool tip.
The index seems to correspond to an entire yField without regard to time interval or category item.
The value appears to be the sum of all of the time intervals or category items for the yField, which winds up being a rather large and meaningless number (please see attached AreaChartToolTipIssue.png).
If you run the attached ColumnChart_AreaSeriesToolTips.txt file and view the tool tips you will see what I mean.
In a Flex area chart you can add a stroke to an area series yField that runs along the very top of the area series yField fill. Everywhere a TimeAxis time interval or a CategoryAxis category item intersected the stroke a tool tip would appear. Tool tips did not appear in the fill area of an AreaSeries yField.
Perhaps we can do something similar here. Everywhere a TimeAxis time interval or a CategoryAxis category item intersects the top of an area series yField fill, show a tool tip if one is setup, etc.
I have not worked with the line series yet, but I noticed on the demo site in the mixed series chart example that a line can have a fill. I imagine that if tool tips where setup in this example – they would only show on the line at the intersection points.