Select Item Showing Dotted Lines While Scrolling Items

Hi,
I am using Smart Gwt-3.0.
"Select Item" having more items it can be having scroll bar.
we are adding items for Select Item by using selectItem.setValueMap(myValueMap).
While moving scroll bar, some dotted lines are appearing and again disappearing.
It is happening only with IE browser.
I observed same thing Smart Gwt Showcase(Smart Gwt 4.0) with IE Browser.
Please find the URL :
http://www.smartclient.com/smartgwt/...bobox_category

Please find the attached screenshot.
Please give me solution for avoiding the dotted lines.


Thanking you

Attached Images

selectItem_dottedLines.png (26.7 KB)