expanding droppable area of rank/order/list drag and drop selection box

i need to expand the droppable area of the "drag and drop" box for a rank/order/list question (because I have so many selectable items, you can't actually put one of them in the box when you scroll to the bottom of the list. i've seen other codes that expand the size of the box visually, but the droppable area remains the same. any code or suggestion is helpful. im a bit of a novice when it comes to coding, but as long as i know where to put it and the variables I need to change, i'm good.