Series users hover on should be highlighted in chart popover
Originally, for column charts with multiple series displayed in a single popover, we talked about highlighting the item users were hovering on within the popover, something like this (though perhaps it should be bolder, rather than just a different color):
We haven't implemented this piece of the design yet.
From discussions on https://gitlab.com/gitlab-org/gitlab-ce/issues/60620, it sounds like this change could help with overall chart accessibility. This is something we should consider adding in.