# Welcome to the Highcharts Gantt JS (gantt) Options Reference

These pages outline the chart configuration options, and the methods and properties of Highcharts objects.

Feel free to search this API through the search bar or the navigation tree in the sidebar.

# tooltip.positioner

A callback function to place the tooltip in a custom position. The callback receives four parameters: `labelWidth`, `labelHeight`, `point`, and `ctx`, where point contains values for `plotX` and `plotY` telling where the reference point is in the plot area, and `ctx` is the tooltip context (so that arrow-functions can access the same context as a normal function using `this`). Add `chart.plotLeft` and `chart.plotTop` to get the full coordinates. Since v12.6.0, the callback receives `ctx`.

To find the actual hovered `Point` instance, use `this.chart.hoverPoint`. For shared or split tooltips, all the hover points are available in `this.chart.hoverPoints`.

Since v7, when tooltip.split option is enabled, positioner is called for each of the boxes separately, including xAxis header. xAxis header is not a point, instead `point` argument contains info: `{ plotX: Number, plotY: Number, isHeader: Boolean }`

Since v12.2, the tooltip.fixed option combined with tooltip.position covers most of the use cases for custom tooltip positioning.

The return should be an object containing x and y values, for example `{ x: 100, y: 100 }`.