The Gantt chart uses Scheduler internally, so the change applies to it as well.
I’m not able to reproduce the problem with the following config anymore:
dp.scale = 'Week';
dp.cellWidth = 100;
dp.useEventBoxes = 'Never';
dp.cellDuration = 1440;
dp.cellGroupBy = "Month";
dp.cellWidth = 100;
dp.cellWidthSpec = "Fixed";
dp.timeHeaders = [
{groupBy: "Month", format: "MMMM yyyy"},
{groupBy: "Week", format: "d"}
];
dp.useEventBoxes = "Always";
dp.days = 300;
Sometimes, the old version of the library gets cached so you can verify that.
If the problem still persists, could you please post a full config that reproduces the problem?