Legend shows no value when mouse is over vertical gridline

Hello,

When the mouse is directly over the vertical gridline, the legend shows no values.

Example can be seen here with the AUD and Euro prices:

https://software.es.net/react-timeseries-charts/#/example/currency

Start by reproducing the issue in the currency example at https://software.es.net/react-timeseries-charts/#/example/currency, placing the mouse directly over a vertical gridline. Trace the legend and gridline interaction, and consider the issue done when the AUD and Euro values remain visible at that position.

Written by the indexing model from the issue text.