I added several different items on both sides, in the squad and in the shelter, and I was able to see all the items and drag them up and down without any problems.
Wait... drag them. I've been trying to move the black bar up or down (does nothing) or the mouse wheel (moves one pixel at a time). There's a way to get to bottom that is actually effective?
There is 80 itens in both sides and i could drag till the end without problems.