When multiple datapoints of a line or area chart have the same x and y value, the tooltip is displayed only for the series that reside on the top-most z-index.
The idea is to get all the possible values and display a tooltip with all the matching values

Kibana Cross Issues

• Visual Builder shows wrong term in tooltip kibana#30932
• Show datapoints belonging together when hovering over them kibana#4885

Checklist

• every related Kibana issue is listed under Kibana Cross Issues list
• kibana cross issue tag is associated to the issue if any kibana cross issue is present