If you go to the question replace values in an array (after my edit goes through) you'll notice that the second code area has a scrollbar because the contents are 2px too wide for the area it's in. This seems odd to me, because the contents use a fixed-width font. Could the width be expanded by 2px to account for the last couple pixels of the last character in such a situation? It just seems visually odd to be able to scroll for 2px in a field with fixed-width characters.
This is a sample code space to illustrate my point; why can I scroll for 2 pixels?