Large listbox choppy in IE8 Only?

Hi everyone,

I have a really frustrating issue with a user who insists on using compatibility mode on the entire site because of 1 listbox that is choppy in IE8 but smooth in compatibility mode. It's smooth in Firefox and other browsers as well. But for some reason in IE8 only, the asp:ListBox (which has 10k+ items) doesn't scroll cleanly so he is complaining that he has to put on compatibility mode to get it smooth.

Problem is, this screws up the entire rest of the site functionality and rendering.

I've tried to force compatibility mode for that one page but it's not working. The page is a master page-based page, so that may have something to do with it.

I had the listbox inside an ajax expander panel, but I took that out.

I even got to the point where I created a new simple web site with nothing more than a listbox, populated it with 10,600 items, and see the exact same thing in IE8. Stock mode is choppy, compatibiliti view is smooth.

I've tried substituting out other .net controls for the listbox(telerik, componentone) but neither of those work either.

Has anyone noticed that the listbox in IE8 is choppy with large amounts of data? Yet other browsers aren't?

Is there someone way to appease this person who prefers to have 1 inch work over having 1 mile work?