Data onover / onout not reliably called when moving between different series with same x-value

[grantcox]

Description

I want to show some information based on which datapoint is currently highlighted - much like a tooltip. This additional data involves template rendering so is a little expensive to generate, so I'd like to update it only when the highlighted data point actually changes.

Using data.onover, data.onout and tooltip.grouped = false almost achieves what I want, the only problem is that the onout for a series is only called when highlighting a completely separate x-axis value, not when highlighting another series value at the same x-axis value. This means that trying to compare two series at the same point in time works "one way" (as each onover is called in turn), but then stops updating.

I can get the desired behavior to work by using the tooltip.onshow and tooltip.onhide, but both of these callbacks are executed for every mouse movement even when there has been no significant change - there's no definitive "tooltip is no longer being shown" callback (afaict). To avoid expensive template re-rendering I'd need to debounce these calls and see if there was a net change over time.

Is this the intended behavior? The setOverOut implementation (and cache usage), looks like it was intended to call data.onout for each datapoint as soon as the cursor moves outside the shape bounds - potentially multiple points could be "over" concurrently, but once moving outside the shape bounds the respective onout should run immediately, rather than "once all shapes are out".

Steps to check or reproduce

Here is a JSFiddle demonstrating these two cases: https://jsfiddle.net/6m9ay5Lh/4/

[netil]

Hi @grantcox, thanks for the post. I'll re-check the scenario if there're points to improve on this.

[netil]

@grantcox, released the 3.6.2 with the fix.

And one reminder, when tooltip.grouped=false is set, data.onxxx event fires with the "sensitivity".
The default is bar.sensitivity=2, which means the approximation distance of the shape to fire the event.

If don't want redundant event firing at the point of crossing the boundary of shapes, set the sensitivity value to 0 as follows.

bar: {
    sensitivity: 0
},

[grantcox]

Thank you @netil , both for the changes to data.onover/out and for the suggestion about the bar sensitivity. I was out of the office last week and I won't have a chance to test / integrate these changes in the coming week, but I really appreciate your efforts and responsiveness. Thank you!