API to Expand Collapse all parents in Gantt Chart
Currently, there is no option to call a function to expand and collapse all elements of a Gantt chart. Some API like chart.expandAll("level1"), chart.collapseAll("level1")
Joyce Chau commented
Are the collapse(), expand(), and toggleCollapse() functions still included in the API? I currently don't see them in Highcharts v8.2.2.
It's not part of the API, but there are three methods to achieve that: