idiosyncrasies in horizontal bar chart hover with a line

[chriddyp]

(forwarding on from the dash community forum: https://community.plot.ly/t/hover-showing-wrong-labels-in-barchart-scatter-graph/8867/4)

https://plot.ly/~Ireneg555/4/#plot

Example:

User noticed a few things:

• Hover switches back and forth from bar to line unpredictably
• User can't hover over the second bar ("cables")

[alexcjohnson]

Man, we should just make closest the default hovermode - see also #778. But also I guess in this case compare should still be able to be y (like it is with just a horizontal bar chart), not x like I guess it reverts to when you add the scatter trace.