start date for Gantt chart
webix.ui({
view: "gantt",
scaleStart: new Date(2020, 5, 1),
scaleEnd: new Date(2020, 5, 30),
url: "https://docs.webix.com/gantt-backend",
});
If the property is not defined it will take the highest start_date value from the dataset. Note that if neither data nor scaleStart/scaleEnd is defined the start date will be the current date and the end one - a month later.