gantt.ignore_time is never called

I have a gannt chart working but no matter what I try I can’t get the weekends to be hidden.

I did have it so that the weekend class was set to disp;ay: none; but I didn’t think that was a good idea.

Note the console.log('ignore time') in the function, you will notice that it will never be printed to the console.

Does anyone have any ideas?

        gantt.config.scale_unit = "month";
        gantt.config.step = 1;
        gantt.config.date_scale = "%F, %Y";
        gantt.config.min_column_width = 50;
        gantt.config.scale_height = 90;



        gantt.config.work_time = true; //removes non-working time from calculations 
        gantt.skip_off_time = true;    //hides non-working time in the chart
        gantt.config.readonly = true;

        var weekScaleTemplate = function(date){
            var dateToStr = gantt.date.date_to_str("%d %F");
            var endDate = gantt.date.add(gantt.date.add(date, 1, "week"), -1, "day");
            return dateToStr(date) + " - " + dateToStr(endDate);
        };

        gantt.config.subscales = [
            {unit:"week", step:1, template:weekScaleTemplate},
            {unit:"day", step:1, date:"%D %d" }
        ];

        // 0 refers to Sunday, 6 - to Saturday
        gantt.ignore_time = function(date){
            console.log('ignore time')
           if(date.getDay() == 0 || date.getDay() == 6)
              return true;
        };


        $('#gannt').dhx_gantt({
            data: demo_tasks
        });

Can you please provide a demo? Everything seems to work as expected in our demos
docs.dhtmlx.com/gantt/snippet/04424eca