Problems in advanced customizing edit boxes in IE8

If I ever try to edit my bottom javascript in the advanced customizing page in IE8, it is a massively frustrating experience and something is busted. Here's what I see.

1. I scroll to a place that I want to edit using either the scroll bar or the mouse wheel.
2. I click on the line I want to edit with the mouse in order to place the cursor in the appropriate spot.
3. Within seconds, the edit box window scrolls somewhere else so I can no longer see where the cursor is.
4. If I use something like the right arrow key, then it scrolls back so I can see the cursor again and I can try to edit again, but this process will repeat over and over again.

I describe the problem here for bottom javascript, but I've seen the same issue in the other edit boxes in that page as along as they have enough data in them to lead to multiple screens worth of scrolling.

I have no idea why it does this. I've never seen this issue in IE8 in any other web page, though I admit that I don't use IE8 regularly. I'm only using it in this case because I keep IE8 logged in on one of my other accounts (the one I don't use that often).

FYI, I don't normally do much editing in these edit boxes because they are so constrained in size, but when all you're trying to do is fix a small error or make a small change, a direct edit is still the fastest way to get the job done (if it didn't have this problem).