Index: core.js
===================================================================
--- core.js	(revision 5904)
+++ core.js	(working copy)
@@ -167,7 +167,8 @@
 					type ?
 						this.style :
 						this,
-					name, jQuery.prop( this, options[ name ], type, i, name )
+					name, jQuery.prop( this, options[ name ], type, i, name ),
+					type ? this : null
 				);
 		});
 	},
@@ -1038,7 +1039,7 @@
 		return ret;
 	},
 
-	attr: function( elem, name, value ) {
+	attr: function( elem, name, value, parent ) {
 		// don't set attributes on text and comment nodes
 		if (!elem || elem.nodeType == 3 || elem.nodeType == 8)
 			return undefined;
@@ -1108,6 +1109,16 @@
 				// Set the alpha filter to set the opacity
 				elem.filter = (elem.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 (elem.filter=="alpha(opacity=100)")
+				{
+					elem.removeAttribute('filter');
+
+					// If there was a class-based opacity assigned, re-set this to 100%.
+					if (parent && parent.currentStyle && parent.currentStyle.filter)
+						elem.filter = "alpha(opacity=100)";
+				}
 			}
 
 			return elem.filter && elem.filter.indexOf("opacity=") >= 0 ?