Non-empty options.markers.discrete Array causes invisible tooltip marker in line chart

[mouxdev]

Description

Using the options.markers.discrete Array to stylize only certain markers in a chart causes the tooltip marker to disappear

Steps to Reproduce

1. Create a chart using the standard options from the documentation and add discrete markers

{
    chart: {
      type: 'line'
    },
    series: [{
      name: 'sales',
      data: [30,40,35,50,49,60,70,91,125]
    }],
    xaxis: {
      categories: [1991,1992,1993,1994,1995,1996,1997, 1998,1999]
    },
    markers: {
        discrete: [
            {
                seriesIndex: 0,
                dataPointIndex: 3,
                fillColor: "#000000",
                size: 5
            }
        ]
    }
  }

Expected Behavior

The chart reacts to hovering by showing a tooltip along with a marker indicating which datapoint is being focused on right now on the line (first screenshot)

Actual Behavior

The chart reacts to hovering by showing only the tooltip (second screenshot)

Screenshots

Reproduction Link

Link to codepen reproducing this error

[idpaterson]

#3715 released in 3.37.2 fixes a related problem with discrete markers that clears the way for a workaround to this invisible tooltip issue. By configuring the chart with markers: { size: 0.000001, ... } you will have effectively invisible markers as desired, but the markers will appear as expected on hover. Attempting this workaround in any version from 3.33.2 to 3.37.1 inclusive results in the tooltip sticking in the upper left rather than dynamically positioning and the markers still did not show on hover.