I decided to give you a script solution because I was interested in this myself, and it actually took a bit to figure out.The scrolling frame property that determines how much the scroll bar can go is the second Y value of CanvasSize if you want to set it in the properties window, otherwise, it would be the CanvasSize Offset. This just loops through it and when it gets to the end, it goes back up to the beginning.
local max = script.Parent.CanvasSize.Y.Offset
for i=1,max do
script.Parent.CanvasPosition = Vector2.new(0,i)
if i==max then
i=1
end
wait()
end