mouseover event and setSelection only works after click, bug?

[Raul Perez]

Hi!

I have 2 related charts and I'm trying to show the tooltips at the same time once the user's mouse is over any of the charts.

So, I did something like this for the first chart chart_1

google.visualization.events.addListener(this.chart_1, 'onmouseover', (event) => {
    this.chart_2.setSelection([event])
});

However, unexpected behaviour occurs.

The tooltip of  chart_2 does not appear while the mouse is over the chart_1 until I explicitly click on the chart_2, once I click on it, both tooltips are synchronized.

Is this expected? Is it a bug?

Any idea?

Thanks!