When the page is loaded initially the tab strip get cut off in IE8. Once a postback or ajax request is made the full tabstrip is visible. The tabs are created dynamically in the code behind.
The attached image has a view of the tabs in IE9 on the top and IE8 on the bottom. You can see the scroll buttons of the tabs on the IE8 version on the far right, but you cannot see the missing tabs when performing a scroll.