I had a problem with the Smooth Slider 2.4 upgrade not displaying sliders properly in Internet Explorer 9. Works fine with all the other browsers (not sure about older IE versions). Part of the sliders were displaying below the slider box area, obfuscating the text in that area. I had this problem on two sites, but not on a third. I discovered that on one site with the problem I had H2 text on the page before the [smoothslider] shortcode, and on the other site with the problem I had an empty H2 start and end tag before the shortcode. I moved the text to after the slider on first site, and in HTML edit mode removed the extraneous tags in the other, and the problem went away.