Added the PieSeries.SliceToolTipFormat, SliceToolTipFunc, ChildSliceToolTipFormat, and ChildSliceToolTipFunc properties, which can be used to supply pie slice tooltips.
Updated stacked charts to show each data point's actual value in the label instead of the stacked value.
修补程序
Fixed a bug where connecting to a Remote Desktop with an already-visible chart could throw an exception.