Well, lets see, you want something like Kent79, a smooth transition, my best beat would be that you need to review the grid theme and the converyor.nut module, and search for this words for some ideas ---
Conveyor.nut:
stride,
transition_swap_point,
transition_progress,
function on_transition,
o.on_progress( o.m_base_progress + move_progress, var )
grid:
function on_progress
you need somehow that in the "second to the last row" (that would be something like : last_row = obj.len()-2)
call some maths in the on_progress and tiggrer the redraw while you are pressing down or up and finish it when you stop to hold up or down.