Currently when using a custom tooltip, the x and y values are supplied as arguments and can be used to provide the tooltip with information.
However when the `shared:true` property set, for example with the trackball, no information is provided. In your demos, where the default EJ2 tooltip is used, there is information about the datums.
Could this same information be passed to a custom tooltip? I.e. provide x + y of datums when `shared:true`.