renderMarkers

updates all markers on the page

void renderMarkers();

var marker1 = gantt.addMarker({ ...});
var marker2 = gantt.addMarker({ ...});
var marker3 = gantt.addMarker({ ...});
 
gantt.renderMarkers();

Details

This method is defined in the marker extension, so you need to enable the marker plugin. Read the details in the Adding Vertical Markers article.