Scrolling issue on IE7

[nccuong]

Dear all,

I am facing an issue with scrolling menu (on my site is horizontal menu), I have captured an image to demonstrate this issue but I do not know how to upload it to this site, so I will show you all the step to re-produce this issue:

1) Navigate to the following link by IE7: http://www.udm4.com/demos/extension-scrolling.php

2) Press Ctrl+ or Ctrl- to resize the page

3) Navigate to Demos -> Configurations and scroll down the submenu, you can see the result when you move your mouse to scroll down button

I would really appreciate if anyone help me about this.

Thanks,
Cuong Nguyen