This event is fired when the user holds the left mouse button down and drags the mouse pointer in a Grid control. The EVENT-DATA-1 and EVENT-DATA-2 data items contain the column and the row number (respectively) of the cell where the dragging started. While dragging the X, Y, Start-X and Start-Y properties contain the same values as EVENT-DATA-1 and EVENT-DATA-2. This event is not fired if the user drags header cells. For this purpose see the MSG-BEGIN-HEADING-DRAG event.