shows the grid area of the Gantt chart
//hides the grid area of the Gantt chart gantt.config.show_grid = false; gantt.init("gantt_here");
gantt.config.show_grid = false is useful when you need to hide the grid area of the Gantt chart quickly while gantt.config.show_chart = false serves to hide the timeline area. If you work in a simple layout, you'd better not use these two options together as it may cause an unexpected result. Instead of it, you should change the configuration of the layout via gantt.config.layout.
The show_grid config will only work if you have not changed the default configuration of the layout via gantt.config.layout. In case you have configured a custom layout, then you have to create several custom configurations and to switch between them to hide/show the grid.
Related sample: Gantt. Toggle grid (custom layout)