I'm not sure if this is possible to fix, but I'll describe it anyway. On a question Calculate correct values to use in layout_weight? if I press my mouse's scroll button down on the code block, I can move my mouse around and scroll to areas not actually defined by the code block.
You can see what's happening below:
I would expect it to only scroll to areas scrollbar would be allowed to go.
I believe this just started happening after I updated to Google Chrome 14 (14.0.835.163 under Windows), so it's possibly this is a bug in Chrome (tagging as discussion for now).