In the Events tab, click the Add button and select the event you want to use. You can then customize the settings for that event.
https://dotsnel.com/

Based on @Jorge solution I created a universal function that will work in pie or bar charts:

```
const legendItemHover = (event) => {
const { chart: legendHoveredChart } = event.target;
const { legend, tooltip } = legendHoveredChart;
for (const item of legend.allItems) {
item.legendItem.on('mouseover', () => {
const data = item?.series?.data[item.index] || item.data[0];
tooltip.refresh(data);
legend.allItems.forEach((itm) => itm.setState('inactive'));
item.setState('hover');
}).on('mouseout', () => {
tooltip.hide();
legend.allItems.forEach((itm) => itm.setState('normal'));
});
}
};
```

pie chart plotOptions:
```
{
pie: {
events: {
afterAnimate(event) {
legendItemHover(event);
},
},
}
}
```

bar chart plotOptions:
```
{
series: {
events: {
afterAnimate(event) {
legendItemHover(event);
},
},
}
}
```

How to when legend item hovering for show all data label (for each legend) in spline or any chart type?

Solution:
http://jsfiddle.net/h1czaysg/1/

Tested in Chrome 62.

This seems almost like a bug to me. For example, in this chart:
http://jsfiddle.net/M5j2c/1/

I want to bind a behavior to mouse over of both a pie wedge and a legend item. If I hover over the pie, the wedge highlights, the legend item highlights, and my event is triggered. However, if I hover over the legend item, I get the first two behaviors, but no event. This seems inconsistent. I am implementing the jquery solution, but it would be nice if this was built in.

@Patrick, your approach with addressing the legend-items is much better and cleaner.
In the future, Highcharts will revolve more around CSS styling and class names, so this will not change.

Perhaps a slightly better approach that I use is to target the legend item itself instead of just the text. Here is an example:
http://jsfiddle.net/LAbQA/1/

I wanted to add that the approach you posted requires us to know the classes and element types used to render the chart. If this ever changes, it would force us to have to change as well. Just a thought...

That is exactly what I do, I just thought it would be nice again to have some hover options without having to create an event handler.

I wrote a custom event handler to refresh/hide the tooltip when hovering over a legend. It would be nice if this was natively supported in the apis.

bump bump... first thing i went to try

Ditto for mouseover/mouseout events on axes. Particularly x-axis. I'd very much like to show the total for all the columns in one timeframe tick of the x-axis when the User hovers over the x-axis label text! Similary, would need the index of the tick on the x-axis.

Another possibility might be to add an option like "showTooltipsOnLegendItemHover" handling this. Most probably with a bit more handy name :)