generates a background image for the timeline area instead of rendering actual columns' and rows' lines
Available only in PRO Edition
gantt.config.static_background = true; gantt.init("gantt_here");
This functionality is available in the PRO edition only.
Since v6.2 this config renders PNG background AND any cells that have CSS class attached to them via the timeline_cell_class template function.
If you need to revert to v6.1 behavior (that is to render just the background image), use the static_background_cells config:
gantt.config.static_background_cells = false;