Autoscroll

Hello! I find some solutions to create autoscroll. These solutions put the top part of the new element as the top of the whole element, I’m trying to put the bottom of the new element as the bottom of the whole element. I don’t know if I explain myself correctly, I’ve attached a drawing of what I’m trying to explain. Does anyone know if this is possible?


I want to go from the first picture to the second when I create the blue element.

Thanks u.