What styles are you applying, because this horizontal scroll is not the same as our default?
As you can see in this demo with many tasks: https://www.htmlelements.com/react/demos/gantt/many-tasks/

The horizontal scroll is under the tasks and also under the table.

You can also send us a demo here or to support@jqwidets.com

Best Regards,
Svetoslav Borislavov

Smart UI Team