Comment 4 for bug 537375

This is not an intended behavior , the problem is that the scrollbars behave/appear differently within the same theme in different applications.

I didnt notice this until i was actually trying to scroll-down in a firefox window , attaching screenshot> notice there is a gap which makes it seem that there is still some page left , while notice the scrolbar of the other window , the stepper is styled differently for firefox and thunderbird.