Why does Outlook 2010 not redraw the email list as I drag the scroll bar?

When I am dragging the scroll bar up or down to scroll through an email pane in Outlook 2010, the email list doesn't redraw until I let go of the scroll bar. However, if I am using the mouse wheel to scroll, the list updates on every scroll.

In working with certain WPF controls that exhibit this same behavior, I am theorizing that Outlook does this to be "more efficient". However, I'd sometimes rather sacrifice efficiency for convenience, so I'd much rather have the email pane scroll much in the same way that an HTML page scrolls when dragging the scroll bar. In WPF, you can disable this redraw-on-release behavior for controls that implement this behavior, so I am wondering if Microsoft gave us a way to do the same for email panes.

Whenever a new folder is selected from the left pane, dragging the scroll bar will not redraw the email list (which is also called "smooth scrolling").

But it will work once you have scrolled till the end of that folder page by page. Let me explain how:

Say you have 75 mails in a particular folder of your inbox and 25 mail items are displayed on screen at a time. Go to that folder and once the first 25 mails are displayed, press page down key two times so that you scroll to second and third listing of the mails in that folder (or scroll to the end of list using mouse). Once you have done that, try dragging the scroll bar, it will redraw the email list like you wanted!! Smooth scrolling will work now.

Hope this helps.