Comment 3 for bug 455412

I have no idea how autoscrolling is implemented, but if it adds images to the
document DOM then the prettyprint side of things work as designed. It sounds
really scary to me that we modify the document DOM for autoscrolling, that can
send off all sorts of wierd things in the document (mutation events will be
notified, scripts executing on a timer will see a modified DOM).

Personally i would prefer to see autoscoll insert things into the chrome instead
which would take care of all of the above problems. There are other
alternatives, but I won't suggest them here since I think they will just add to
the current wrong-ness