The onColumnMove event is fired when a user completes drag and drop moving of calendar columns (on drop).
You can use this event to cancel the moving (by calling args.preventDefault() method).
When this event is called, the calendar columns (columns.list property) still show the original positions. To read the new values, use the onColumnMoved event handler.
Available in the calendar component since version 2022.3.5381.
DayPilot.Calendar.onColumnMove(args);