Set Gantt cell or column attribute GanttRunMove to Move, Copy or Remove to let move run boxes outside the row. Optionally set it only for dragging with a key like Shift, Ctrl or Alt or by different mouse button.
Define API event
OnGanttRunDrop
. It is called both during moving and also on drop. Provide here you custom action especially for drop.
Define onmousedown HTML event of the tag to be dragged. Return false from it to suppress selecting text. For IE define also onselectstart and return false to suppress selecting.
In the onmousedown code you can call
DragByMouse
API function to attach some HTML to mouse to simulate the dragging.
For tablets define also ontouchstart with the same code as the onmousedown.
Define API event
OnMouseUp
to handle the dropping into grid. Here you can provide any action like changing the cell by SetString, adding new row by AddRow,
adding new Run box into Gantt chart by AddGanttRunBox, etc.