Created Unassigned: Error ChartLegendItemStyle [16214]

Dear Torsten

First thanks for the great libary.

I am using you doughnut chart in a simple app and I get the following error in the Output Window.

I have search my Solution for ChartLegendItemStyle, and it is indeed not present, neither in code nor in a binding expression.

Error: BindingExpression path error: 'ChartLegendItemStyle' property not found on 'Windows.UI.Xaml.Controls.ContentPresenter'. BindingExpression: Path='ChartLegendItemStyle' DataItem='Windows.UI.Xaml.Controls.ContentPresenter'; target element is 'De.TorstenMandelkow.MetroChart.ChartLegendItem' (Name='null'); target property is 'Style' (type 'Style')

What causes this problem?

Kind Regards
Graham