Hi Imran Javed Zia,
RadChart does not support multiple tooltips and it would not be possible to achieve the desired effect.
If this is a requirement for your project you can check the built-in TrackBallBehavior in our new RadChartView component (hover the chart in the lower left corner to see the trackball tooltip here
-- the same is applicable for the WPF version). Note, however, that RadChartView is still a BETA version and while it has go-live license,it will be officially released with Q1 2012.
the Telerik team
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