Not only entire rows but individual Cell values or properties can be exchanged between multiple grids by simple drag and drop gestures.
This is done by:
dragModel.beforeDropis implemented in draggable grid to prevent default removal of dragged rows from it.
dropModel.dropcallback is implemented in droppable grid to copy fields of interest from draggable grid.
Exchange of cell values / properties is not limited to plain grids but can also be extended to grouped rows and tree grid using the same technique.