Index: css.js
===================================================================
--- css.js	(revision 6414)
+++ css.js	(working copy)
@@ -67,6 +67,16 @@
 				// Set the alpha filter to set the opacity
 				style.filter = (style.filter || "").replace( /alpha\([^)]*\)/, "" ) +
 					(parseInt( value ) + '' == "NaN" ? "" : "alpha(opacity=" + value * 100 + ")");
+
+				// If all we have is 100% opacity, remove the filter attribute to prevent DirectX boggles.
+				if (style.filter=="alpha(opacity=100)")
+				{
+					style.removeAttribute('filter');
+
+					// If there was a class-based opacity assigned, re-set this to 100%.
+					if (elem && elem.currentStyle && elem.currentStyle.filter)
+						style.filter = "alpha(opacity=100)";
+				}
 			}
 
 			return style.filter && style.filter.indexOf("opacity=") >= 0 ?