I'll qualify (I was in a hurry and loathe this way of screen navigation so much, I wanted to get my oar in :-)): scrollbars, cursor keys and mouse wheel scrolling - which is how SONAR and Windows applications navigate - all work in the same way. Ie. if I want to look at what's under what I'm currently looking at, I move the scrollbar down, I press the down cursor or I drag the mouse wheel down. A click and drag the contents reverses this completely, so it's inconsistent (and illogical IMHO).
That said, I keep on wanting to hold down the middle mouse button and drag the mouse to scroll like in IE - I'd support that as it's consistent with how all other navigation elements work in SONAR (and is logical!).