Thank you for the questions. We have already planned to provide add a TriggerMode property to the trackball behavior so stay tuned for the next beta release.
Also, in order to show the tooltip with information for more than one data point, please have a look at the attached file, the tooltip article under the features folder to be more precise. It contains the chart documentation which is not yet online.
Please write again if you have other questions.
the Telerik team
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