With the newest version of the control, the requested behavior is achievable. You can use code like the following:
RadChart1.DefaultView.ChartArea.DataSeries.Definition.Visibility = SeriesVisibility.Collapsed;
to set the visibility to collapsed. The control will internally rebind and span the rest of the series to occupy the space vacated by the first series, which was hidden.
I hope this information helps.
the Telerik team
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