I've inherited an application that changes content images. When the item is two big to fit in its parent container it uses a scroll bar. When we change back to a smaller item the scroll bar remains at the same dimensions and we can see black space around the image by dragging the scroll bar. I've been looking all over for information on resetting the scroll bar according to the dimensions of the current contents but I can't seem to find it. Is this a common occurrence or is this something that shouldn't happen (meaning the app is doing something unusual)?