I have two sets of Y data using the exact same X data.
I have a hovertool in “vline” mode and “nearest” line_policy. It should give the same X value and the same index value for both lines.
I attached two pictures to illustrate this.
On the first picture the index is off by 1 unit and we can see the box is not attached on the same point for the blue line.
On the second picture, I zoomed in, the hover works better.