I create a number of ScatterSeries in code for various ice cream flavors (may not be relevant) like so:

ScatterSeries ss = new ScatterSeries();

// various properties set which probably don't matter for the discussion

TextBlock tb = new TextBlock();

tb.SetBinding(TextBlock.TextProperty, new Binding("Item.ToolTip"));

ss.ToolTip = tb;

The ToolTip property in the underlying data is the flavor of the ice cream represented by the series.  I expect that when I mouse over a point on the chart, the user will see the ToolTip for that point and tell them the flavor of ice cream (along with the series badge).

The behavior that I see is that when I first hover over a point on the first series (first meaning the first one I hover over - doesn't matter which one I choose - in this case I chose the Chocolate Chunk series) the tooltip pops up like so:

I expect this one to look like so (though it would be a different flavor):

It will, however, pop up correctly once I've moused over the point on a different series.

Again, doesn't matter which series I choose - the first point I hover over will be blank (with the series badge displayed but no flavor text) until I hover over a point on a different series. If I were to hover over a bunch of points all from the first series, they all exhibit this behavior, once I hover over a point from a different series, then tooltips are OK for the points in the first series.

Ideas?

Thanks,

Matt