From https://github.com/catapult-project/catapult/issues/3252

V2spa currently displays invisible dots at every commit, and icons for alerts. It displays a tooltip when users hover over the dots/icons. This has a few problems discussed in 3252.
V2spa should explore some of the solutions proposed in 3252.
Also, the dots are not performant. V2spa should display the tooltip for the nearest data point when the user hovers over the chart without using dots.