﻿Along with tooltip and pan/zoom behaviors, RadChart provides a trackball behavior through the ChartTrackballBehavior class. This behavior can display a vertical line across the chart plot area and also to display little visual indicators (circles by default) at points where the trackball line crosses the visualization of a series object. For example when the trackball line crosses a line series line segment, a small circle is drawn highlighting the value of the series at this point.