In many applications, when you click in the scrollbar trough above the slider, your view moves up by one page. When you click below the slider, you view moves down by one page.
On the Result and Table Data tabs, the view moves by just one row, exactly the same as when you click on the up/down arrows. This isn't critical, but when you have thousands of rows of data, the ability to go page by page makes it much easier to navigate through them.
On the Objects and History tabs, clicking in the scrollbar trough moves the view by one page, as it should.
I am seeing this behavior in version 4.05 on WinXP Pro SP2.