shows/hides markers on the page
Available only in PRO Edition
var marker1 = gantt.addMarker({ ...});
var marker2 = gantt.addMarker({ ...});
var marker3 = gantt.addMarker({ ...});
gantt.config.show_markers = false;// hides all 3 markers
This functionality is available in the PRO edition only.
This option is defined in the marker.js extension, so you need to enable the marker plugin. Read the details in the Adding Vertical Markers article.