I have HTML CSS DIV Scroll bars on this client's website (the old site used frames and we are trying to make it more search engine and user friendly) and when you go to the address http://www.missionkayaking.com/test/kayaks/index.php
you will see the bottom right area has a scroll panel.
However, if you click on the Kayak button at the top navigation it will reload the page and won't show the scroll bar. If you go over to the sub navigation on the left hand side and hover over some of the links the scroll bar appears. The same happens if you click on the Lake or River links on the side navigation.
But if you go to the Contact button on the top navigation, it doesn't do this,