You should probably update as version 1.0.5.0 is really dated by now.
Try this. In your datetime picker renderer''s constructor, subscribe to the grid''s Leave event.
grid.Leave += new EventHandler(grid_Leave);
Then in the event handler, end the editing on the cell.
private void grid_Leave(object sender, EventArgs e)
{
this.Grid.CurrentCell.EndEdit();
}